A backdoor trojan virus demolished my OS last week, so I feel your pain. I thought that trojans were benign, merely providing a hacker with access to your computer should it be found hackable during various port scans. However, it did do significant damage to my OS, and I doubt that anyone ever actually hacked into my computer. I got rid of the virus fairly prompty, but the damage was already done. I could barely run any programs; I would get error after error regarding .dll problems. I could only use Windows Explorer occasionally, so backing up my system was a very time consuming and frustrating ordeal. Most times, I would click on My Computer and immediately get an error that would force me to reboot (which was a problem in itself; due to a faulty motherboard, anytime I would reboot using the restart button, the monitor would just go off and the computer would stall. The same would happen if I completely turned it off, then turn it on again. I had to actually turn off the power to my computer for 15 seconds, then hit the power switch in order to boot up again. Very annoying!).

Since reformatting and installing the new motherboard and XP, it's been smooth sailing. I think the only solution for you is a format, Ab.