Well, I use Malwarebytes' Anti Malware program, and I have the full version of it, if you want to try it.
If you can know the exact location of the virus, you can use Microsoft's recovery console, which comes on the Windows CD/DVD, to go there and remove it, then log on windows in safe mode, open regedit and search for all the keys containing the virus's executable name.
I use Windows Vista, and I'm using AVG at the moment with other minor malware/spyware protection software.