If you isolate top two antivirus software Norton and MacAfee and look at all other antivirus software you will find that majority of these antivirus software have free personal edition which provides little less features then paid edition but does protects your computer from viruses.
Some time back we had wrote about one of promotion offer on Avira AntiVir Premium edition, if you were unfortunate to grab Avira AntiVir Premium edition free key then here is some thing for you, A latest version of Avira AntiVir 9 Free Edition from Avira labs. Avira AntiVir 9 now searches and removes viruses even more efficiently.
Ninth generation of Avira AntiVir include enhanced scan engine, parental control and support for netbooks. AviraAntiVir 9 also comes with built in Spyware protection system.
Features of Avira AntiVir 9 Personal Edition
1. Protection against viruses, worms and Trojans
2. AntiDialer protection against expensive dialers
3. AntiRootkit protection against hidden rootkits
4. Faster Scanning up to 20% faster
5. New User Interface
6. AntiPhishing protection against phishing
7. AntiSpyware protection against spyware and adware
8. NetbookSupport for laptops with low resolution
9. QuickRemoval eliminates viruses at the push of a button
Screenshot of Avira AntiVir 9 Free Personal Edition