SC 13D

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 13D

Under The Securities Exchange Act of 1934

(Amendment No.     )*

CDW Corporation

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

12512N105

(CUSIP Number)

Mark B. Tresnowski

Madison Dearborn Partners, LLC

Three First National Plaza, Suite 3800

Chicago, Illinois 60602

(312) 895-1000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

COPY TO:

James S. Rowe

Kirkland & Ellis LLP

200 E. Randolph Drive

Chicago, Illinois 60601

(312) 861-2000

May 29, 2007

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Page 1 of 11 Pages

CUSIP No. 12512N105 13D Page 2 of 11 Pages

1	NAMES OF REPORTING PERSONS / I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
	VH MergerSub, Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
	(a)  ¨
	(b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions)
	OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Illinois

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7  SOLE VOTING POWER
	None
	8  SHARED VOTING POWER
	17,648,062 shares of Common Stock
	9  SOLE DISPOSITIVE POWER
	None
	10  SHARED DISPOSITIVE POWER
	None

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,648,062 shares of Common Stock (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)	¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	22.4% of Common Stock (See Item 5)
14	TYPE OF REPORTING PERSON (See Instructions)
	CO

CUSIP No. 12512N105 13D Page 3 of 11 Pages

1	NAMES OF REPORTING PERSONS / I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
	VH Holdings, Inc.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
	(a)  ¨
	(b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions)
	OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7  SOLE VOTING POWER
	None
	8  SHARED VOTING POWER
	17,648,062 shares of Common Stock
	9  SOLE DISPOSITIVE POWER
	None
	10  SHARED DISPOSITIVE POWER
	None

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,648,062 shares of Common Stock (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)	¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	22.4% of Common Stock (See Item 5)
14	TYPE OF REPORTING PERSON (See Instructions)
	CO

CUSIP No. 12512N105 13D Page 4 of 11 Pages

1	NAMES OF REPORTING PERSONS / I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
	Madison Dearborn Partners, LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
	(a)  ¨
	(b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS (See Instructions)
	OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(D) OR 2(E)	¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION
	Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7  SOLE VOTING POWER
	None
	8  SHARED VOTING POWER
	17,648,062 shares of Common Stock
	9  SOLE DISPOSITIVE POWER
	None
	10  SHARED DISPOSITIVE POWER
	None

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
	17,648,062 shares of Common Stock (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions)	¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
	22.4% of Common Stock (See Item 5)
14	TYPE OF REPORTING PERSON (See Instructions)
	OO

Item 1. Security and Issuer.

The class of equity security to which this statement relates is the Common Stock, par value $0.01 per share (the “Common Stock”), of CDW Corporation, an Illinois corporation (“CDW”). The principal executive offices of CDW are located at 200 N. Milwaukee Avenue, Vernon Hills, Illinois 60061.

Item 2. Identity and Background.

This statement is being jointly filed by each of the following persons pursuant to Rule 13d-1(k) promulgated by the Securities and Exchange Commission (the “Commission”) pursuant to Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”):

(i) VH MergerSub, Inc. (“MergerSub”), an entity organized under the laws of the state of Illinois, by virtue of the fact that it may be deemed beneficial owner of 17,648,062 shares of Common Stock of CDW that are subject to the Support Agreement as described below;

(ii) VH Holdings, Inc. (“Holdings”), an entity organized under the laws of the state of Delaware, by virtue of its being the sole shareholder of MergerSub; and

(iii) Madison Dearborn Partners, LLC (“Madison Dearborn Partners”), a Delaware limited liability company, at whose direction each of the above-referenced entities has been formed,

all of whom are collectively referred to as the “Reporting Persons.” The Reporting Persons have entered into a Joint Filing Agreement, dated the date hereof, a copy of which is filed with this Schedule 13D as Exhibit A (which is hereby incorporated by reference) pursuant to which the Reporting Persons have agreed to file this statement jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Exchange Act. The Reporting Persons expressly disclaim that they have agreed to act as a group other than as described in this statement.

Pursuant to Rule 13d-4 of the Exchange Act, the Reporting Persons expressly declare that the filing of this statement shall not be construed as an admission that any such person is, for the purposes of Section 13(d) and/or Section 13(g) of the Exchange Act or otherwise, the beneficial owner of any securities covered by this statement held by any other person.

Certain information required by this Item 2 concerning the executive officers and directors of MergerSub, Holdings and Madison Dearborn Partners is set forth on Schedule A attached hereto, which is incorporated herein by reference.

The address of the principal business office of each of MergerSub, Holdings and Madison Dearborn Partners is Three First National Plaza, Suite 3800, Chicago, Illinois 60602.

Each of Holdings and MergerSub was formed in May of 2007 by affiliates of Madison Dearborn Partners to acquire CDW pursuant to that certain Agreement and Plan of Merger among CDW, MergerSub and Holdings, dated as of May 29, 2007 (the “Merger Agreement”). The Merger Agreement provides, among other things, that MergerSub will merge with and into CDW, as a result of which CDW will become a wholly-owned subsidiary of Holdings. Holdings is the sole shareholder of MergerSub, which was formed for the purpose of effecting the Merger (as defined in the Merger Agreement). CDW is a provider of multi-branded information technology products and services. Madison Dearborn Partners is primarily engaged in serving as the general partner for private equity funds engaged primarily in the business of investing and managing private equity investments.

Page 5 of 11 Pages

None of the Reporting Persons nor, to the best of their knowledge, the Reporting Persons’ executive officers, directors or managing directors (as applicable) has, during the last five years, been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

None of the Reporting Persons nor, to the best of their knowledge, the Reporting Persons’ executive officers, directors or managing directors (as applicable) has, during the last five years, been party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Information with respect to each Reporting Person is given solely by such Reporting Person and no Reporting Person assumes responsibility for the accuracy or completeness of the information furnished by another Reporting Person. The Reporting Persons expressly disclaim that they have agreed to act as a group other than as described herein.

Item 3. Source and Amount of Funds or Other Consideration.

As more fully described in Item 4 hereof, MergerSub, Holdings and each of Michael P. Krasny Revocable Trust U/A/D July 1, 1993, Circle of Service Foundation, Inc., MPK-DT 2005 GRAT I, MPK-DT 2006 GRAT II, MPK DT 2006 GRAT III, MPK 2006 GRAT I, MPK 2006 GRAT II, MPK-DT 2006 GRAT I (collectively, the “Stockholders”) entered into a Support Agreement (the “Support Agreement”), dated May 29, 2007, as an inducement for MergerSub and Holdings to enter into the Merger Agreement. An aggregate of 17,648,062 shares of Common Stock and options to purchase an additional 35,080 shares of Common Stock are subject to the terms of the Support Agreement. Each Stockholder’s obligations under the Support Agreement are individual obligations and are not joint or several obligations of the Stockholders.

The transactions contemplated by the Support Agreement are not expected to require the material expenditure of any funds.

The information set forth in Item 4 of this Schedule 13D is hereby incorporated herein by reference.

Item 4. Purpose of Transaction.

Pursuant to the Support Agreement, each Stockholder has agreed, among other things, to vote, or provide a consent with respect to, such Stockholder’s shares of Common Stock that are subject to the Support Agreement (the “Subject Shares”) at any meeting of holders of Common Stock of CDW or in connection with any other circumstances upon which a vote or other approval is sought: (i) in favor of the adoption of the Merger Agreement and in favor of the transactions contemplated by the Merger Agreement and any actions required in furtherance thereof; (ii) against any other merger, consolidation, combination, sale of substantial assets, sale of capital stock, sale of debt securities, reorganization, recapitalization, tender offer, dissolution, liquidation or winding up of or by CDW or any of its subsidiaries or any Takeover Proposal (as defined in the Merger Agreement) with respect to CDW (other than the transactions contemplated by the Merger Agreement); (iii) against any amendment of CDW’s bylaws or certificate of incorporation or other action or agreement that would materially impede, frustrate, hinder or delay the approval of the Merger Agreement or any of the transactions contemplated therein; and (iv) against any other action, plan agreement or proposal that could reasonably be expected to result in a breach in any respect of any covenant, representation or warranty or any other obligation of CDW under the Merger Agreement. Pursuant to the Support Agreement, each Stockholder is obligated to vote (or cause to be voted) in person or by proxy such Stockholder’s Subject Shares at any meeting of the stockholders of CDW on the matters and in the manner described in the immediately preceding sentence.

Page 6 of 11 Pages

In addition, subject to certain limited exceptions, each Stockholder has agreed under the Support Agreement not to (i) sell, transfer, pledge or otherwise encumber, assign or otherwise dispose of any of such Stockholder’s Subject Shares or any option or other right to acquire any shares of capital stock of CDW (an “Option”), (ii) enter into any contract, agreement, option or other arrangement or understanding with respect to the direct or indirect sale, short sale, transfer, pledge, assignment or other disposition of such Stockholder’s Subject Shares or Options, (iii) grant any proxy, power-of-attorney, option or other authorization in or with respect to such Stockholder’s Subject Shares or Options, (iv) deposit such Stockholder’s Subject Shares or Options into a voting trust or enter into other arrangements or agreements with respect to the voting of such Stockholder’s Subject Shares or Options or (v) exercise any rights of dissent or appraisal in connection with the transactions contemplated by the Merger Agreement.

The purpose of entering into the Support Agreement was to induce MergerSub and Holdings to enter into the Merger Agreement and to facilitate the approval of the transactions contemplated thereby.

Pursuant to the Merger Agreement, MergerSub will be merged with and into CDW, as a result of which CDW will become a wholly owned subsidiary of Holdings, and each issued and outstanding share of capital stock of MergerSub shall be converted into and become a share of capital stock of CDW. The Reporting Persons intend, and the Merger Agreement provides, that the parties to the Merger Agreement will take all actions necessary so that the directors of MergerSub immediately prior to the Effective Time (as defined in the Merger Agreement) shall become the directors of CDW immediately after the Effective Time. Pursuant to the Merger Agreement, the articles of incorporation of CDW shall be amended and restated in their entirety. Holdings intends to cause CDW to terminate the registration of its shares of Common Stock under the Exchange Act upon completion of the Merger.

Except as set forth in the preceding paragraphs, as of the date hereof, the Reporting Persons do not have any present plans or intentions which result in or relate to any of the actions described in subparagraphs (a) though (j) of Item 4 of Schedule 13D.

Notwithstanding the foregoing, the Reporting Persons reserve the right to effect any such actions as any of them may deem necessary or appropriate in the future.

The foregoing discussion is qualified in its entirety by reference to the Merger Agreement and the Support Agreement, the terms of each of which are incorporated herein by reference to Exhibits B and C hereto.

The information set forth in Item 3 of this Schedule 13D is hereby incorporated herein by reference.

Item 5. Interest in Securities of the Issuer.

(a)–(b) Prior to May 29, 2007, none of the Reporting Persons owned or was the “beneficial owner” (as defined in Rule 13d-3 promulgated under the Exchange Act) of any shares of Common Stock. Upon the execution of the Support Agreement, MergerSub and Holdings may be deemed to have acquired “beneficial ownership” (as defined in Rule 13d-3 promulgated under the Exchange Act) of the Subject Shares under the Support Agreement. Pursuant to the Support Agreement, MergerSub and Holdings may be deemed to have the shared power to vote the Subject Shares under the Support Agreement with respect to the matters set forth in the Support Agreement. None of MergerSub or Holdings has either sole or shared dispositive power over the Subject Shares pursuant to the terms of the Support Agreement. As of

Page 7 of 11 Pages

May 29, 2007, the aggregate number of Subject Shares under the Support Agreement totaled 17,648,062 and constituted approximately 22.4% of the issued and outstanding Common Stock. There are Options to acquire 35,080 shares of Common Stock that are only issuable upon the exercise of outstanding Options held by the Stockholders, which upon the exercise of such options will be subject to the Support Agreement and deemed to be additional Subject Shares.

Holdings, as the sole shareholder of MergerSub, may be deemed to have acquired beneficial ownership of the Subject Shares pursuant to the terms of the Support Agreement and to have the shared power to vote the Subject Shares with respect to the matters set forth in the Support Agreement.

Madison Dearborn Partners, by virtue of its role in directing the formation of each of the above-referenced Reporting Persons, may be deemed to have acquired beneficial ownership of the Subject Shares pursuant to the terms of the Support Agreement and to have the shared power to vote the Subject Shares with respect to the matters set forth in the Support Agreement.

The Reporting Persons expressly disclaim that they have agreed to act as a group other than as described herein. The filing of this Schedule 13D by MergerSub, Holdings and Madison Dearborn Partners shall not be considered an admission that such Reporting Persons, for the purpose of Section 13(d) of the Exchange Act, are the beneficial owners of any of the Subject Shares.

All of the percentages calculated in this Schedule 13D are based upon an aggregate of 78,748,711 shares of Common Stock outstanding on March 31, 2007 as disclosed in CDW’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2007, which was filed with the Commission on May 10, 2007.

(c) Except for the transactions described herein, there have been no other transactions in the securities of CDW effected by the Reporting Persons in the last 60 days.

(d) To the knowledge of the Reporting Persons, only the Stockholders have the right to receive or the power to direct the receipt of dividends from, or proceeds from the sale of, the Subject Shares.

(e) Inapplicable.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Except for the agreements described above or in response to Items 3 and 4 of this Schedule 13D, which are hereby incorporated herein by reference, to the best knowledge of the Reporting Persons, there are no contracts, arrangements, understandings or relationships (legal or otherwise) between the persons enumerated in Item 2 of this Schedule 13D, and any other person, with respect to any securities of CDW, including, but not limited to, transfer or voting of any of the securities, finder’s fees, joint ventures, loan or option agreements, puts or calls, guarantees of profits, divisions of profits or loss, or the giving or withholding of proxies.

Page 8 of 11 Pages

Item 7. Material to be filed as Exhibits.

Exhibit A—Schedule 13D Joint Filing Agreement, dated June 8, 2007, by and among Madison Dearborn Partners, Holdings and MergerSub.

Exhibit B—Agreement and Plan of Merger, dated as of May 29, 2007, among Holdings, MergerSub and CDW (incorporated by reference to Exhibit 2.1 to CDW’s Current Report on Form 8-K filed with the Commission on May 31, 2007).

Exhibit C— Support Agreement, dated as of May 29, 2007, by and among Stockholders, Holdings and MergerSub.

Page 9 of 11 Pages

SIGNATURES

After reasonable inquiry and to the best of each of the undersigned’s knowledge and belief, each of the undersigned certify that the information set forth in this statement is true, complete and correct.

Date: June 8, 2007

VH MERGERSUB, INC.
By:	/s/ Benjamin D. Chereskin
Name:	Benjamin D. Chereskin
Its:	President and Assistant Secretary
VH HOLDINGS, INC.
By:	/s/ Benjamin D. Chereskin
Name:	Benjamin D. Chereskin
Its:	President and Assistant Secretary
MADISON DEARBORN PARTNERS, LLC
By:	/s/ Mark B. Tresnowski
Name:	Mark B. Tresnowski
Its:	Managing Director and General Counsel

Page 10 of 11 Pages

SCHEDULE A

Directors and Executive Officers of MergerSub: MergerSub is governed by a Board of Directors consisting of two Directors. The two Directors are Benjamin D. Chereskin and George A. Peinado. Mr. Chereskin is a Managing Director and Mr. Peinado is a Director, respectively, of Madison Dearborn Partners. In addition, Mr. Chereskin is the President and Assistant Secretary and Mr. Peinado is the Vice President and Secretary, respectively, of MergerSub. The principal business address of Benjamin D. Chereskin and George A. Peinado, each of whom is a United States citizen, is c/o Madison Dearborn Partners, LLC, Three First National Plaza, Suite 3800, Chicago, Illinois 60602, telephone (312) 895-1000.

Directors and Executive Officers of Holdings: Holdings is the sole shareholder of MergerSub and is governed by a Board of Directors consisting of two Directors. The two Directors are Benjamin D. Chereskin and George A. Peinado. Mr. Chereskin is a Managing Director and Mr. Peinado is a Director, respectively, of Madison Dearborn Partners. In addition, Mr. Chereskin is the President and Assistant Secretary and Mr. Peinado is the Vice President and Secretary, respectively, of Holdings. The principal business address of Benjamin D. Chereskin and George A. Peinado, each of whom is a United States citizen, is c/o Madison Dearborn Partners, LLC, Three First National Plaza, Suite 3800, Chicago, Illinois 60602, telephone (312) 895-1000.

Directors and Executive Officers of Madison Dearborn Partners: Madison Dearborn Partners is responsible for forming the other Reporting Persons described herein. John A. Canning, Jr. is the Chairman and Chief Executive Officer of Madison Dearborn Partners, and each of Paul J. Finnegan and Samuel M. Mencoff is Co-President of Madison Dearborn Partners. The following individuals are Managing Directors of Madison Dearborn Partners: Brian L. Newman, David F. Mosher, James N. Perry Jr., Benjamin D. Chereskin, Timothy P. Sullivan, Nicholas W. Alexos, Timothy M. Hurd, Robin P. Selati, Thomas S. Souleles and Mark B. Tresnowski. Mr. Tresnowski is also General Counsel of Madison Dearborn Partners. In addition, Michael J. Wilson is the Vice President and Chief Financial Officer of Madison Dearborn Partners. The principal business address of each of these individuals is c/o Madison Dearborn Partners, LLC, Three First National Plaza, Suite 3800, Chicago, Illinois 60602, telephone (312) 895-1000. Each Managing Director and executive officer of Madison Dearborn Partners is a United States citizen.

Page 11 of 11 Pages

EX-99.(A)

Exhibit A

AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13D

Each of the undersigned hereby acknowledges and agrees, pursuant to the provisions of Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, as amended, that the Schedule 13D to which this Agreement is attached as an Exhibit, and any amendments thereto, will be filed with the Securities and Exchange Commission jointly on behalf of the undersigned.

Date: June 8, 2007

MADISON DEARBORN PARTNERS, LLC
By:	/s/ Mark B. Tresnowski
Name:	Mark B. Tresnowski
Its:	Managing Director and General Counsel
VH HOLDINGS, INC.
By:	/s/ Benjamin D. Chereskin
Name:	Benjamin D. Chereskin
Its:	President and Assistant Secretary
VH MERGERSUB, INC.
By:	/s/ Benjamin D. Chereskin
Name:	Benjamin D. Chereskin
Its:	President and Assistant Secretary

EX-99.(C)

Exhibit C

SUPPORT AGREEMENT

This SUPPORT AGREEMENT (the “Agreement”), dated as of May 29, 2007, is made by and among the parties listed under “Shareholders” on the signature pages hereto (each individually, a “Shareholder” and, collectively, the “Shareholders”), VH Holdings, Inc., a Delaware corporation (“Parent”), and VH MergerSub, Inc., an Illinois corporation and a wholly-owned subsidiary of Parent (“Sub”). Capitalized terms used herein but not otherwise defined herein shall have the meanings ascribed to such terms in the Merger Agreement (as defined below).

WHEREAS, concurrently herewith, Parent, Sub and CDW Corporation, an Illinois corporation (the “Company”), are entering into an Agreement and Plan of Merger, dated as of the date hereof (the “Merger Agreement”), providing for the merger of Sub with and into the Company, with the Company as the surviving corporation (the “Merger”), upon the terms and subject to the conditions set forth in the Merger Agreement;

WHEREAS, as of the date hereof, the Shareholders beneficially own, or have, individually or together, complete investment authority over, and have, individually or together (or upon exercise or exchange of a convertible security will have) the power to vote and dispose of the number of shares of common stock, par value $0.01 per share, of the Company (the “Common Stock”) set forth opposite their name on Schedule A attached hereto (the “Owned Shares” and, together with any securities issued or exchanged with respect to such shares of Common Stock upon any recapitalization, reclassification, merger, consolidation, spin-off, partial or complete liquidation, stock dividend, split-up or combination of the securities of the Company or any other change in the Company’s capital structure or securities of which such Shareholder acquires beneficial ownership after the date hereof and prior to the termination hereof, whether by purchase, acquisition or upon exercise of options, warrants, conversion of other convertible securities or otherwise, collectively referred to herein as, the “Covered Shares”); and

WHEREAS, as a condition to the willingness of Parent and Sub to enter into the Merger Agreement, Parent and Sub have required that the Shareholders agree, and in order to induce Parent and Sub to enter into the Merger Agreement, the Shareholders have agreed, to enter into this Agreement with respect to (a) the Covered Shares and (b) certain other matters as set forth herein.

NOW, THEREFORE, in consideration of the foregoing and the mutual covenants and agreements contained herein, and intending to be legally bound hereby, the parties hereto hereby agree as follows:

ARTICLE I.

SUPPORT AGREEMENT

Section 1.1 Support Agreement. The Shareholders hereby agree that during the Voting Period (as defined below), at any meeting of the shareholders of the Company, however called, or at any adjournment thereof or in any other circumstances upon which a vote or other approval is sought, the Shareholders shall (i) when a meeting is held, appear at such meeting or otherwise cause the Covered Shares to be counted as present thereat for the purpose of establishing a quorum and (ii) vote (or cause to be voted) in person or by proxy the Covered Shares in favor of the Merger, the adoption of the Merger Agreement and the transactions contemplated by the Merger Agreement and (iii) vote (or cause to be voted) the Covered Shares against (A) any extraordinary corporate transaction (other than the Merger), such as a merger, consolidation, business combination, tender or exchange offer, reorganization, recapitalization, liquidation, sale or transfer of all or substantially all of the assets or securities of the Company and any of its Subsidiaries (other than pursuant to the Merger), dividend or distribution, (B) any change in the corporate structure of the Company or its Subsidiaries or any amendment to the Company’s articles of incorporation or bylaws (other than pursuant to the Merger Agreement), (C) any Takeover Proposal or other proposal made in opposition to or in competition with the consummation of the Merger, (D) the election of a group of individuals to replace a majority or more of the individuals on the Board of Directors of the Company as of the date hereof and (E) any other action, agreement, proposal, plan or arrangement that could reasonably be expected to result in a breach of a representation, warranty or covenant of the Company under the Merger Agreement or would in any manner prevent or materially impede, interfere with or delay the Merger, the approval of the Merger Agreement or the consummation of any of the transactions involving Parent and Sub contemplated by the Merger Agreement. For the purposes of this Agreement, “Voting Period” shall mean the period commencing on the date hereof and ending immediately prior to any termination of this Agreement pursuant to Section 5.1 hereof. The Shareholders agree that, during the Voting Period, they will not, in their capacity as shareholders of the Company, act by written consent on any matter. The provisions of this Section 1.1 shall apply whether or not the Company breaches any of its representations, warranties, covenants or agreements under the Merger Agreement.

ARTICLE II.

REPRESENTATIONS AND WARRANTIES OF PARENT AND SUB

Parent and Sub hereby represent and warrant to each Shareholder as follows:

Section 2.1 Valid Existence. Each of Parent and Sub is a corporation duly organized, validly existing and in good standing under the laws of the state of its incorporation and each has the requisite corporate power and authority to carry on its business as it is now being conducted.

Section 2.2 Authority Relative to This Agreement. Each of Parent and Sub has all necessary corporate power and authority to execute and deliver this Agreement, to perform its obligations hereunder and to consummate the transactions contemplated hereby. This Agreement has been duly and validly authorized, executed and delivered by each of Parent and Sub and, assuming the due authorization, execution and delivery by the other parties hereto, constitutes a legal, valid and binding obligation of each of Parent and Sub, enforceable against each of them in accordance with its terms, except as enforcement may be limited by bankruptcy, insolvency, moratorium or other similar laws relating to creditors rights generally and by general

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equitable principles (regardless of whether such enforceability is considered in a proceeding in equity or at law).

ARTICLE III.

REPRESENTATIONS AND WARRANTIES OF THE SHAREHOLDERS

Each Shareholder hereby represents and warrants to Parent and Sub as follows:

Section 3.1 Authority Relative To This Agreement. Such Shareholder has the legal capacity to execute and deliver this Agreement, to perform its obligations hereunder and to consummate the transactions contemplated hereby. This Agreement has been duly and validly executed and delivered by such Shareholder and, assuming the due authorization, execution and delivery by Parent and Sub, constitutes a legal, valid and binding obligation of such Shareholder, enforceable against such Shareholder in accordance with its terms, except as enforcement may be limited by bankruptcy, insolvency, moratorium or other similar laws relating to creditors rights generally and by general equitable principles (regardless of whether such enforceability is considered in a proceeding in equity or at law).

Section 3.2 No Conflict.

(a) The execution and delivery of this Agreement by such Shareholder does not, and the performance of its obligations under this Agreement by such Shareholder and the consummation by such Shareholder of the transactions contemplated hereby will not, (i) conflict with or violate any law, rule, regulation, order, judgment or decree applicable to such Shareholder, (ii) result in any breach of or constitute a default (or an event that with notice or lapse of time or both would become a default) under any contract to which such Shareholder is a party or (iii) render the provisions of Sections 7.85 and 11.75 of the IBCA applicable to the Merger, the Merger Agreement or this Agreement.

(b) The execution and delivery of this Agreement by such Shareholder does not, and the performance of its obligations under this Agreement will not, require any consent, approval, authorization or permit of, or filing with or notification to, any court or arbitrator or any Governmental Entity, agency or official except for applicable requirements of the Securities and Exchange Act of 1934, as amended.

Section 3.3 Ownership Of Shares. As of the date hereof, such Shareholder has good and marketable title to and is the beneficial owner (within the meaning provided in Rule 13d-3 promulgated under the Securities Exchange Act of 1934, as amended) of the Owned Shares set forth opposite such Shareholder’s name on Schedule A hereto, free and clear of all pledges, liens, proxies, claims, charges, security interests, preemptive rights, voting trusts, voting agreements, options, rights of first offer or refusal and any other encumbrances or arrangements whatsoever with respect to the ownership, transfer or other voting of the Covered Shares. Such Shareholder does not beneficially own or exercise control or direction over, directly or indirectly, any securities of the Company except as set forth on Schedule A hereto. Other than as provided in this Agreement, such Shareholder is not currently obligated to grant and has not granted any proxy in respect of any of the Covered Shares and such Shareholder has not entered into any

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voting trust, vote pooling or other agreement with respect to the right to vote, call meetings of shareholders or give consents or approvals of any kind as to the Covered Shares. None of the Covered Shares is subject to, or is the subject of, any commitment, undertaking or agreement, the terms of which would affect in any way the ability of such Shareholder to perform such Shareholder’s obligations under this Agreement, or, once acquired by Parent, of Parent to enjoy the full rights of ownership thereof. No proceedings are pending which, if adversely determined, will have an adverse effect on any ability to vote or dispose of any of the Covered Shares.

Section 3.4 Shareholder Has Adequate Information. Such Shareholder is a sophisticated investor with respect to the Covered Shares and has independently and without reliance upon Parent or Sub and based on such information as such Shareholder has deemed appropriate, made its own analysis and decision to enter into this Agreement. Such Shareholder acknowledges that neither Parent nor Sub has made nor makes any representation or warranty, whether express or implied, of any kind or character except as expressly set forth in this Agreement.

Section 3.5 No Setoff. To the knowledge of such Shareholder, there are no legal or equitable defenses or counterclaims that have been or may be asserted by or on behalf of the Company, as applicable, to reduce the amount of the Covered Shares or affect the validity or enforceability of the Covered Shares.

Section 3.6 Reliance. Such Shareholder understands and acknowledges that Parent and Sub are entering into the Merger Agreement in reliance upon such Shareholder’s execution, delivery and performance of this Agreement.

Section 3.7 No Other Representations or Warranties. Except for the representations and warranties expressly contained in this Article III, such Shareholder makes no express or implied representation or warranty with respect to such Shareholder, the Covered Shares, or otherwise.

ARTICLE IV.

COVENANTS OF THE SHAREHOLDERS

Each Shareholder hereby covenants and agrees as follows:

Section 4.1 No Transfer. Other than pursuant to the terms of this Agreement or the Merger Agreement, without the prior written consent of Parent or as otherwise provided in this Agreement, during the term of this Agreement, such Shareholder hereby agrees to not, directly or indirectly, (i) grant any proxies or enter into any voting trust or other agreement or arrangement with respect to the voting of any Covered Shares or (ii) sell, sell short, pledge, assign, transfer, encumber or otherwise dispose of (including by merger, consolidation or otherwise by operation of law), or enter into any contract, option futures contract, short sale, derivative contract or other arrangement or understanding with respect to the direct or indirect assignment, transfer, encumbrance, delivery or other disposition of (including by merger, consolidation operation of law or otherwise), any Covered Shares. Promptly following the date hereof, such Shareholder and Parent shall deliver joint written instructions to the Company and to the Company’s transfer agent stating that the Owned Shares may not be sold, transferred,

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pledged, assigned, hypothecated, tendered or otherwise disposed of in any manner without the prior written consent of Parent or except in accordance with the terms and conditions of this Agreement. If any Covered Shares are acquired after the date hereof by a Shareholder, the foregoing instructions shall be delivered upon acquisition of such Covered Shares. Notwithstanding the foregoing, the Shareholders may transfer (A) up to 284,900 of the Covered Shares by gift to charitable organizations without restriction and (B) up to 1,424,501 of the Covered Shares by gift to charitable organizations provided that prior to, and as a condition of, any such gift, each transferee under this clause (B) shall unconditionally and irrevocably, in accordance with the IBCA and to the fullest extent permitted by applicable law, appoint Parent or its designee, and each of them, as such transferee’s sole and exclusive attorney-in-fact and proxies, with full power of substitution and re-substitution, to vote the transferred Covered Shares and to exercise all voting, consent and similar rights of such transferee with respect to the Covered Shares (including, without limitation, the power to execute and deliver written consents and to cause the Covered Shares to be counted as present for the purpose of establishing a quorum) at every annual, special or adjourned meeting of the holders of the Common Stock and in every written consent in lieu of such meeting, in accordance with clauses (ii) and (iii) of Section 1.1; and provided further that all such transferred Covered Shares shall be certificated and the certificate shall bear a legend that they are subject to the terms of this Agreement and the proxy contemplated by clause (B) of this Section 4.1. Any proxy granted pursuant to clause (B) of this Section 4.1 shall terminate immediately at the same time as this Agreement is terminated in accordance with Section 5.1 hereof.

Section 4.2 Dissent Rights. Such Shareholder covenants that he or she will not exercise any rights of dissent or appraisal provided under the Merger, any applicable laws (including the IBCA) or otherwise in connection with the approval of the Merger or any other corporate transaction considered at the Shareholders Meeting.

Section 4.3 Public Announcement. Such Shareholder shall obtain the written consent of Parent before issuing any press releases or otherwise making any public statements with respect to the transactions contemplated herein, in its capacity as a shareholder of the Company, except as may be required by law with respect to the making of a public statement (in which case, each Shareholder will consult with Parent prior to making such public statement).

Section 4.4 Additional Shares; Notification. Such Shareholder shall as promptly as practicable notify Parent of the number of any new Covered Shares acquired by the Shareholder, if any, after the date hereof. Any such shares shall be subject to the terms of this Agreement as though beneficially owned by such Shareholder on the date hereof. Such Shareholder agrees that such Shareholder will promptly notify Parent in writing upon any representation or warranty of such Shareholder in this Agreement becoming untrue in any material respect or upon an obligation of such Shareholder not being complied with in any material respect.

Section 4.5 No Restraint on Officer or Director Action; Etc. Notwithstanding anything to the contrary herein, each of Parent and Sub hereby acknowledges and agrees that no provision in this Agreement shall limit or otherwise restrict any Shareholder with respect to any act or omission that such Shareholder may undertake or authorize in his or her capacity as a director or officer of the Company or any subsidiary thereof, including any vote that such

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individual may make as a director of the Company with respect to any matter presented to the Board of Directors of the Company. The agreements set forth herein shall in no way restrict any such director or officer in the exercise of his or her duties as a director or officer of the Company or any subsidiary thereof. Each Shareholder has executed this Agreement solely in his or her capacity as the record and/or beneficial owner of his or her Covered Shares and no action taken by such Shareholder solely in his or her capacity as a director or officer of the Company or any subsidiary thereof shall be deemed to constitute a breach of any provision of this Agreement.

Section 4.6 Further Assurances. Subject to Section 4.5 above, such Shareholder hereby agrees to use commercially reasonable efforts to take, or cause to be taken, all actions, and to do, or cause to be done, and to assist and cooperate with the Company and Parent in doing, all things necessary, proper or advisable to consummate and make effective, in the most expeditious manner possible, the Merger and the other transactions contemplated by the Merger Agreement (other than any Takeover Proposal or Superior Proposal), and to carry out the intents and purposes of this Agreement. Subject to Section 4.5, such Shareholder agrees that such Shareholder will not enter into any agreement, arrangement or understanding or make any commitment with any person that would violate any provision or agreement contained in this Agreement.

ARTICLE V.

MISCELLANEOUS

Section 5.1 Termination. This Agreement and all of its provisions shall terminate upon the earlier of (i) the Effective Time, (ii) the termination of the Merger Agreement in accordance with its terms or (iii) written notice of termination of this Agreement by Parent or Sub to Shareholders (such date of termination, the “Termination Date”); except that the provisions of this Article V shall survive any such termination.

Section 5.2 Survival of Representations and Warranties. The respective representations and warranties of the Shareholders, Parent and Sub contained herein shall not be deemed waived or otherwise affected by any investigation made by the other party hereto. The representations and warranties contained herein shall expire with, and be terminated and extinguished upon, consummation of the Merger or termination of this Agreement pursuant to Section 5.1, and thereafter, except in the case of fraud or willful misconduct or any breach by any Shareholder of this Agreement prior to its termination in accordance with Section 5.1, no party hereto shall be under any liability whatsoever with respect to any such representation or warranty.

Section 5.3 Fees And Expenses. Except as otherwise expressly provided in the Merger Agreement, all costs and expenses incurred in connection with the transactions contemplated by this Agreement shall be paid by the party incurring such costs and expenses.

Section 5.4 Notices. All notices, requests, claims, demands and other communications hereunder shall be in writing and shall be given (a) on the date of delivery if delivered personally, (b) on the first business day following the date of dispatch if delivered by a nationally recognized next-day courier service, (c) on the fifth business day following the date of

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mailing if delivered by registered or certified mail (postage prepaid, return receipt requested) or (d) if sent by facsimile transmission, when transmitted and receipt is confirmed. All notices hereunder shall be delivered to the respective parties at the following addresses (or at such other address for a party as shall be specified in a notice given in accordance with this Section 5.4):

if to Parent or Sub:

VH Holdings, Inc.

c/o Madison Dearborn Partners, LLC Three First National Plaza

Chicago, Illinois 60602

Facsimile: (312) 895-1001

Attn: Mark B. Tresnowski, Esq.

with a copy, which shall not constitute notice, to:

Kirkland & Ellis LLP

200 East Randolph Drive

Chicago, Illinois 60601

Facsimile: (312) 861 2200

Attn: Edward T. Swan, P.C.

Michael D. Paley

if to the Shareholders:

Attn: Michael P. Krasny; Michael Tepper.

Sawdust Investment Management Corp.

1622 Willow Road Suite 200 Northfield, IL 60093

Facsimile: (847) 498-1177

with copies to:

Sullivan & Cromwell LLP

125 Broad Street

New York, New York 10004-2498

Facsimile: (212) 558 3588

Attn: W. Jay Clayton, III

Additionally, any notice delivered to any party hereto shall also be given to the Company in accordance with this Section 5.4 at:

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CDW Corporation

200 N. Milwaukee Avenue

Vernon Hills, Illinois 60061

Facsimile: (847) 968-0336

Attn: John A. Edwardson

with copies to:

CDW Corporation

200 N. Milwaukee Avenue

Vernon Hills, Illinois 60061

Facsimile: (847) 968-0303

Attn: Christine A. Leahy

Sidley Austin LLP

One South Dearborn Street

Chicago, Illinois 60603

Telephone: (312) 853-7000

Facsimile: (312) 853-7036

Attn:    Thomas A. Cole, Esq.

   Dennis V. Osimitz, Esq.

Section 5.5 Severability. If any term or other provision of this Agreement is invalid, illegal or incapable of being enforced by any rule of law, or public policy, all other conditions and provisions of this Agreement shall nevertheless remain in full force and effect so long as the economic or legal substance of the transactions contemplated hereby is not affected in any manner materially adverse to any party. Upon such determination that any term or other provision is invalid, illegal or incapable of being enforced, the parties hereto shall negotiate in good faith to modify this Agreement so as to effect the original intent of the parties as closely as possible in a mutually acceptable manner in order that the transactions contemplated hereby be consummated as originally contemplated to the fullest extent possible.

Section 5.6 Entire Agreement; Assignment. This Agreement constitutes the entire agreement among the parties hereto with respect to the subject matter hereof and supersede all prior agreements and undertakings, both written and oral, among the parties hereto, or any of them, with respect to the subject matter hereof. This Agreement shall not be assigned (whether pursuant to a merger, by operation of law or otherwise), except that either Parent or Sub may assign all or any of its rights and obligations hereunder to an Affiliate, provided, however, that no such assignment shall relieve the assigning party of its obligations hereunder if such assignee does not perform such obligations.

Section 5.7 Amendment. This Agreement may be amended by the parties at any time prior to the Effective Time. This Agreement may not be amended except by an instrument in writing signed by each of the parties hereto.

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Section 5.8 Waiver. At any time prior to the Effective Time, any party hereto may (a) extend the time for the performance of any obligation or other act of any other party hereto, (b) waive any inaccuracy in the representations and warranties of any other party contained herein or in any document delivered pursuant hereto and (c) waive compliance with any agreement of any other party or any condition to its own obligations contained herein. Any such extension or waiver shall be valid if set forth in an instrument in writing signed by the party or parties to be bound thereby. The failure of any party to assert any of its rights under this Agreement or otherwise shall not constitute a waiver of those rights.

Section 5.9 Parties in Interest. This Agreement shall be binding upon and inure solely to the benefit of each party hereto, and nothing in this Agreement, express or implied, is intended to or shall confer upon any other Person any right, benefit or remedy of any nature whatsoever under or by reason of this Agreement. However, if after the execution hereof and before the Termination Date the Shareholders should die or become incapacitated, this Agreement shall be binding on the Shareholders’ estate or other legal representative.

Section 5.10 Governing Law. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Illinois, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws thereof.

Section 5.11 Specific Performance; Submission To Jurisdiction.

(a) The parties agree that irreparable damage would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement in the United States District Court for the Northern District of Illinois (unless such court shall lack subject matter jurisdiction, in which case, in any state or federal court located in Illinois), this being in addition to any other remedy to which the parties are entitled at law or in equity under this Agreement.

(b) The parties hereby irrevocably submit to the jurisdiction of the United States District Court for the Northern District of Illinois (unless such court shall lack subject matter jurisdiction, in which case, in any state or federal court located in Illinois) solely in respect of the interpretation and enforcement of the provisions of this Agreement and of the documents referred to in this Agreement, and in respect of the transactions contemplated hereby, and hereby waive, and agree not to assert, as a defense in any action, suit or proceeding for the interpretation or enforcement hereof or of any such document, that it is not subject thereto or that such action, suit or proceeding may not be brought or is not maintainable in said court or that the venue thereof may not be appropriate or that this Agreement or any such document may not be enforced in or by such court, and the parties hereto irrevocably agree that all claims with respect to such action or proceeding shall be heard and determined in such court. The parties hereby consent to and grant any such court jurisdiction over the person of such parties and agree that mailing of process or other papers in connection with any such action or proceeding in the manner provided in Section 5.4 or in such other manner as may be permitted by applicable law shall be valid and sufficient service thereof.

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(c) EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND THEREFORE EACH PARTY HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT SUCH PARTY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (i) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, TO IT THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER, (ii) EACH PARTY UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF THIS WAIVER, (iii) EACH PARTY MAKES THIS WAIVER VOLUNTARILY AND (iv) EACH PARTY HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 5.11(c).

Section 5.12 Headings. The descriptive headings contained in this Agreement are included for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement.

Section 5.13 Counterparts. This Agreement may be executed and delivered (including by facsimile transmission) in one or more counterparts, and by the different parties hereto in separate counterparts, each of which when executed shall be deemed to be an original but all of which taken together shall constitute one and the same agreement.

Section 5.14 Further Assurances. From time to time, at the request of another party and without further consideration, each party hereto shall take such reasonable further action as may reasonably be necessary or desirable to consummate and make effective the transactions contemplated by this Agreement.

[SIGNATURE PAGE FOLLOWS]

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IN WITNESS WHEREOF, Parent, Sub and the Shareholders have caused this Agreement to be duly executed on the date hereof.

VH HOLDINGS, INC.

By:

Name:

Title:

VH MERGERSUB, INC.

By:

Name:

Title:

SHAREHOLDERS:

Michael P. Krasny Revocable Trust U/A/D July 1, 1993

By:

Name:

Title:

CIRCLE OF SERVICE FOUNDATION, INC.

By:

Name:

Title:

MPK-DT 2005 GRAT I

By:

Name:

Title:

MPK-DT 2006 GRAT II

By:

Name:

Title:

Signature Page to Support Agreement

MPK-DT 2005 GRAT I

By:

Name:

Title:

MPK DT 2006 GRAT III

By:

Name:

Title:

MPK 2006 GRAT I

By:

Name:

Title:

MPK 2006 GRAT II

By:

Name:

Title:

Signature Page to Support Agreement

Schedule A

Shareholder	Shares of Common Stock	Options to Purchase Common Stock
Michael P. Krasny Revocable Trust U/A/D July 1, 1993	12,359,779	35,080
Circle of Service Foundation, Inc	431,786	0
MPK-DT 2005 GRAT I	436,538	0
MPK-DT 2006 GRAT II	1,000,000	0
MPK DT 2006 GRAT III	1,000,000	0
MPK 2006 GRAT I	1,000,000	0
MPK 2006 GRAT II	1,000,000	0
MPK-DT 2006 GRAT I	419,959	0
TOTAL:	17,648,062	0