I'll put in my 2 cents here, been in the Computer Business since 1994 and have been fighting Viruses ever since.
The only answer that i would choose acceptable is the one from OhmZoned.
One other User suggested Hirens, alright.
All others, try again.
If you have a Virus that is powerful enough to lock you out of your System, (FBI-Virus for example)you'll need to run a Virus scan in it's own (linux) environment. So download Kaspersky Rescue or the Hirens CD and let the System remove the heavy hitters.
Once you are able to boot into Windows again, still run these: