hmmm... maybe the RAM got damaged? try removing one RAM module and trying to start the computer. if it still doesn't work, replace that RAM module and remove another. that way, if it works, you'll know that you just need new RAM.
EDIT:
I think I found something!You can attempt to repair this file by starting windows setup using the original setup CD-Rom. Select "r" at the first screen to start repair. Do NOT use an OEM "Recovery Disc". Only a valid Windows XP media will work or a disc from the OEM that says "Operating System" may sometimes work depending on how the manufacturer labeled the CD.