Drediock:
My girlfriend's mother had something like this on her PC last month. Tried multiple times to get the thing OFF her machine, and the thing that finally did it was a little app I came across called "VundoFix.exe". Wish I still had the link for it. :\
If you have been hit with the Vundo bug that Hungry described, VundoFix may be a quick and relatively painless way to get you back up and running.
If you're interested in pursuing this suggestion - try Googling "VundoFix.exe" and do some reading on the hits you get. As I recall, it only worked on some variations of the Vundo critter, so it's not a guaranteed fix. However, if you're lucky (like I was) it may work on whichever one you have, and get this issue behind you relatively quickly and without any additional financial cost -- just be sure to scan any fixes you find & download before you try them out. Those malware guys are sneaky bastards.

Other than that, the only other things I can really recommend that you try are other virus scanning utilities, and/or a drive wipe & reinstall (hellishly painful & time consuming - as you probably already know).
Dunno if you know about these guys are not, but here's a few links to free Antivirus programs that work well (though I still use AVG as my primary AV software on my main machine):
Free Regular Antivirus programs:
http://www.free-av.com/http://www.avast.com/This next link is a free app that doesn't just look for virus patterns, but pays attention to what running processes on your machine are doing and preempts suspicious activities (like catching a process that's trying to capture your keystrokes, for example). I really like this one because I've run it alongside AVG for a while now without all the headaches that are typically associated with running multiple AV programs on the same machine:
http://www.threatfire.com/And here's a free online virus meta-scanner. Word of warning with this one though - it tends to bring back a lot of false positives:
http://www.virustotal.com/Dunno if any of this will help out your specific situation, I just figured I'd try the shotgun approach and hope that something I toss up here might help out. If you get a good analysis of your HJT log from a real pro, I'd recommend that you defer to his suggestions over mine (I don't know much about HJT).
Anyway, again, I hope something here helps out and good luck!

-Caz1