I will assume you have done a good run of AV, gotten updates, and removed spyware using a method very similar to the malware warfare guide in my sig. Post a log of a Hijackthis scan as an attachment if you could, so I can see if there are any remnants of anything on your system.
Run the system file checker, with your XP CD in the drive. XP right?
Issue this at the command prompt:
sfc /scannow
The rest of the switches can be found by issuing sfc /? instead.
Let me know if this helps at all.