Avast Free 5, an A-list freeware antivirus app, provides the same steadfast protection of well-known, pricier antivirus programs. Avast is remarkable for both its effectiveness and arguably providing the most complete free antivirus on the market.
AVG Free provides a combined antivirus and antimalware engine, LinkScanner, and e-mail scanning.
Avira AntiVir offers a wide selection of scan customization, letting users fully scan both internal and external hard drives, run a preloaded scan or customize a scan.
ThreatFire offers real-time prevention of virus and malware infections by identifying suspicious behavior as it happens, before malicious code installs itself on your PC.