I Am At My Wits End!

[ZoMBiEXxX]

I am working on a computer for a friend. I replaced the hard drive because it was shot. So I installed the hard drive and a fresh copy of Windows XP Pro. All worked well, he came got it called next day said it was giving him the config system file is missing or corrupt. I have done the repair, I have removed and changed RAM, I have replaced the CMOS battery, I have put tested with a different PSU, I have removed the PCI-E video card and used the onboard, I have ran diagnostic tests on both the HD and the RAM and came back clear, I have even done a reformat and no matter what I have done this error comes back after the computer has been unplugged for about 15 minutes. I do not know what else to do. PLEASE HELP!

 

[montyuk]

just for clarification - when is this message shown?

at post?
during windows startup?
once windows has started?

 

[ZoMBiEXxX]

It is showing after the POST before the Windows loading screen.

 

[montyuk]

sounds like the master boot record is corrupting

unfortunately it sounds like you've already done everything i could think of,
i would check the ram/cmos battery again. i had a similar case a while back with a machine that kept corrupting itself and the ram was the culprit.