Norton would be awesome if it didn't fuck up so much. Every version they release is a load of bollocks. It works perfectly until you actually try to use it and eventually it just fucks up, or won't let you uninstall it. I always end up having to completely remove it from my Hd and install AVG. I've done this so many times.

Anyway, mrdevious, it sounds like your installed OS (XP?) is corrupted or damaged. Restart your PC with your Windows installation CD in your CD drive, and when the option comes up book from disk (at the boot screen it should say "Press any key to Boot from disk" or something similar).

When you've successfully booted from the CD follow the on screen instructions to repair your version of XP. Reboot your computer (not from the CD this time) and see if it's made any difference. If not then boot from the disk again and this time follow the instructions to reformat your drive and reinstall Windows. This should fix the problem. If not then it's either a completely new, as-of-yet undetectable virus or it may be an actual psychical hardware problem.

Hope this helped in some way.