Avast Antivirus home (home use only)

Homepage: http://www.avast.com

Download link: https://www.avast.com//download-software

Operating Systems: Windows

Description: Complete solution with  antivirus, antispyware, antirootkit, web shield, p2p protection, im protection, email scanner, automatic updates, resident protection. Home use only. Requires email registration. You receive a registration code by email. It is valid for one year. After this period you have to reregister. Registration at : http://www.avast.com/eng/home-registration.php

Probably the best one. Recommended

Avira AntiVir Personal Edition (home use only)

Homepage: http://www.free-av.com/

Download link: http://www.free-av.com/en/download/1/avira_antivir_personal__free_antivirus.html

Operating Systems: Windows, linux

Description: Complete solution with antivirus, antispyware,  antirootkit,automatic updates, resident protection. Home use only. No email scanner. You will see ads during the updates..

Avg Free (home use only)

Homepage: http://free.avg.com/

Download link: http://free.avg.com/ww.download?prd=afe

Operating Systems: Windows

Description: Complete solution with antivirus, antispyware,  automatic updates, resident protection. Home use only. You will see ads during the updates..

Bit Defender free edition  (home use only)

Homepage: http://www.bitdefender.com

Download link: http://www.bitdefender.com/site/Downloads/

Operating Systems: Windows

Description: antivirus, antispyware, automatic updates. Home use only. No email scanner or resident scanner.  Scans only on demand  Recommender only as secondary scanner.

Clamwin

Homepage: http://www.clamwin.com/

Download link: http://www.clamwin.com/content/view/18/46/

Operating Systems: Windows

Description: Antivirus, antispyware,email scanner, automatic updates. Completely free. The  email scanner works only with Microsoft Outlook and not with Outlook express. No resident scanner.  Scans only on demand. Recommender only as secondary scanner.

Comodo Internet Security

Homepage: http://antivirus.comodo.com/

Download link: http://www.personalfirewall.comodo.com/download_cis.html

Operating Systems: Windows

Description:Antivirus, firewall, antispyware,email scanner, automatic updates. Completely free. The only free for business with resident scanner και email scanner. Released In October 2008. Firewall is Superb. Antivirus recommended only as secondary scanner for now.