I had a nasty malware on my mother-in-law's computer a couple of weeks ago (Google redirect and some sort of other error I now forget). I tried AVG scan & Malwarebytes with no luck. I had the XP reinstall sitting on my desk ready to just wipe it and start over. As a last resort, I tried ComboFix. They recommend using it in conjunction with any of the several malware/virus sites that will review your scan logs, but I just ran it, figuring I had nothing to lose. Voila! It worked. Found a rootkit and another virus the others had overlooked.
On the other hand, if I'd just done a reinstall at the beginning, I would have saved a couple of days of effort... .
g.
