Free virus protection and optimization
A free and safe companion: Avast Free Antivirus
Free and comprehensive protection suite
Free and simple antivirus software from Microsoft
Amir Antivirus
Avast Premier Antivirus
One of the best antiviruses for Windows
Sophos Home Security Free
A quality PC and Mac antivirus and web filter
Kaspersky Security Scan
Virus alert? Use Kaspersky for free malware indentification