Computer Won[t Turn on

You should check your monitor cables and settings. Next open the case and reseat your video card. If that doesn't work change the monitor or use your monitor on another system, if it works then it is your video card that is bad.

If the above doesnt work then make sure that you do not have a second video card in it (like 1 onboard, 1 added), if you do, switch the monitor cable to the other one and see what happens,
maybe flash the bios, or on some video cards, you can flash the video bios.

If your boot attempts do not produce any error beeps, it's most likely your video adapter or possibly RAM. Make sure your video cards, connections and cables are firmly seated and that your RAM chips are firmly seated.

Also, make sure you don't have some kind of CMOS virus, that can really mess things up.

When you restored your system, did you format the drive or just reinstall Windows over itself? I had a virus wipe out my Win98SE, and Windows was never the same until I installed it on a clean drive.

There is nothing wrong with the hardware.
Hopefully the virus just messed up your power management. (The PC is always in dose.)
Check power management in the BIOS first.
If not, it is time to "zero fill" the hard drive, or start over with a different hard drive.
(Depending on how pressed you are for time.)
This experience is why there is backup, and why a full backup (complete hard drive image) is a must.
I hope no valuable data was destroyed in this "incident".
That you can recover any version of Windows from a serious virus attack is hype.
Every true expert will tell you "use a backup device".
Regards, Chris

When the computer tries to boot are there any error messages at all ?? I would try Booting with a Windows 95B or Win95C boot disk and then see if the system is finding the CD-Rom Drive if so install you Windows OP System you might think about installing Windows 98SE seeing how you might have problems ReActivateing you Winxp OP System with Microsoft