For computer users – more so with Windows operating systems – system security is always a big concern among its users. So, below I compiled a list of free Anti-Virus software. With this being said, I am not promising that there isn't paid portions of these programs that offer a greater amount of security that could could potentially be interested in. However, the free software, along with other pieces of free software can do just as well.

Avast Free Antivirus
AVG AntiVirus Free 2013
Avira Free Antivirus 13
Microsoft Security Essentials