I agree with Mik3, reformating the drives and reloading the OS from disc would be the best way to get rid of any viruses, do not just run the System Restore, since this could also be infected if it resides on another partition on the drive...
Do not install more than one antivirus at a time, you have a fair chance of wrecking your windows installation.
You can run multiple malware checkers.
I'd run 'ccleaner' then 'combofox', 'Malware Bytes Anti-malware' and 'Spybot Search & Destroy'.
Combofix must be downloaded freshly, it's only valid for a few days each build.
Search 'combofix bleepingcomputer' to get it's info & download page.
The others have updaters built in.
Another option is to download and burn the current 'DrWeb live CD'. You boot the machine directly from the CD and it scans without windows running.
It can also often dis-infect .exe files rather than deleting them, so has a better change of not damaging the system than some other programs.