Avast Anti-Virus is pretty good, Japavidols. I would recommend it over Scan McAfee or Norton Anti-Virus.
http://www.avast.com/free-antivirus-downloadNEVER install AVG.
They are the absolute worst as far as tying up your computer and darned near impossible to uninstall later.
There are a large variety of useful utilities, including Freeware to keep your computer running at top efficiency.
Please don't hesitate to look me up regarding these as I've had quite a bit of experience in removing malware, virii, spyware, keyloggers, fly-by-nights, and rapeware.
Hope This helps !