Posted 22 October 2010 - 12:51 PM
I would try a reboot, and mash F8 during the boot process. Select "Last know good configuration" and if that doesn't work try "Safe-mode". Run an anti-virus scan in whatever mode works (preferably Safe-Mode).
After this I would run "sfc.exe /scannow" from the run dialog in either mode (you may need an XP CD for this).