Exhibit 31.2

Certification

I, Richard H. Marsh, certify that:

1.I have reviewed this report on Form 10-K/A of FirstEnergy Corp.; and

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of

     the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

Date: March 21, 2007

/s/ Richard H. Marsh

Richard H. Marsh

Chief Financial Officer