Malwarebytes Anti-Malware
Spybot Search & Destroy
HiJackThis (download and post the log file, I can help you I've studied for HiJackThis)
AVG (Full version)
Norton 360 (If you're able to pay)
Avast
Kaspersky
These are one of the best Security Programs you can have, you're supposed to have one on your computer, even If you do have more than 1 the best thing to do is don't run scans at the same time, or else your computer can crash.
I suggest you download HiJackThis, and Post a log file here. It's not hard to use it's really easy, but here's a tutorial anyways:
http://www.bleepingcomputer.com/tutorials/tutorial42.html