I have the same problem also. Used
www.anitvirus.com and it found one virus in two locations. ADW TENGET.A the files were c:\prgramfiles\filesubmit\shine xp\nlp38.exe , and c:\windows\system\winstart001.exe..deleted them.
Ive installed the patch, and stoped sharing my folders (read somewhere else about that)
ALSO I ran a scan with norton and it didnt find anything. While i was writing this it found the Backdoor.sdbot virus..Source: C:\temp\V60K3Fa06112.. deleted it. That has something to do with IRC so i dont think that would be the problem, but the first time i have ever encountered it.
After deleting and patching I havent had the problem in about an hour.