Certain applications have stopped working, seemingly out of nowhere. I detected Welchia on my machine, so I thought it was responsible, but after removing it, the problems remained. So I ran Registry Clean Expert, it found a TONNE of problems, fixed them, and the problem remains. I'd have thought a problem like this would be viral or registry... I get one of these messages with certain programmes: With MS Word 97: The instruction at "0x77e9c578" referenced memory at "0x00000000". The memory could not be "read". With Cool-Edit Pro 2: The exception Floating-point invalid operation. (0xc0000090) occurred in the application at location 0x0058f004. Also, when I try to shut down, explorer.exe is unable to end itself, and I sometimes lose my active desktop when restarting. Any ideas? Thanks.

The cool-edit pro 2 error sounds like a runtime error in the program itself. MS Word 97 is a little archaeic and does have a lot of bugs. Tried Word 2000 or Word XP. The explorer problem can sometimes be attributed to a lot of paging to the hard disk because you've used up all your RAM, a file system corruption (especially common with FAT32, but not so much with NTFS) or the virus has left a trail of destruction on your PC as it left. That answers your question about the virus - the virus may have done some permanent damage to your Windows 2000, Word 97, cool-edit or any other program's installation. I'd suggest backing up virsu-free data (update your virus definitions and scan the hard disks with your antivirus first), FULLY uninstalling the applications, running CHKDSK /F /V /R, disk cleanup and disk defragmenter over all hard disks and seeing if the problem still occurs. IF not, re-install your software again. If the problem recurs, your best bet is probably to re-format your hard disk from Windows 2000 Setup using the NTFS file system and re-install Windows 2000 and all of your file systems. Also make sure you set sensible pagefile sizes. Post a follow-up to let me know how you get on.

It seems a different virus was to blame. The previously undetected Pate.b has been removed and the problems are now gone. Thanks for your help, anyway, though.