Spy Sweeper my friend, not anti virious, you want a spyware remover.
Actually you need both spyware programs and a good antivirus. The best security move is to have more than one good spyware program. Many times one will detect problems that the other won't and vice versa.
If you want to be super secure try out a program called "Ultimate Boot CD". It allows you to run AV programs from a CD without loading your OS. If you compile the CD from an uninfected computer then there's no way a virus or worm can hide from that type of scan. A good online virus scanner is likewise as good but I'd suggest having a high speed connection for those unless you have a few days to run your scan.
Texas_Raiders, you sir need some improved security on that machine. Run ,don't walk, down to your local computer store and get a copy of Mc Affee or Norton AV.

It'd also help to run your Windows Update until it says there's nothing left to download.