AVG Anti-Virus Free Edition
Antivirus and antispyware protection for Windows available to download for free

NEW! LinkScanner® Active Surf-Shield checks web pages for threats at the only time that matters - when you're about to click that link.

    *  Award-winning antivirus and antispyware
    * Real-time safe internet surfing and searching
    * Quality proven by 80 million of users
    * Easy to download, install and use
    * Protection against viruses and spyware
    * Compatible with Windows 7, Windows Vista and Windows XP

AVG Anti-Virus Free Edition download and installation is only available for single computer use for home and non commercial use.

http://free.avg.com/download-avg-anti-virus-free-edition?cmpid=fr_bn_free_670



avast! Free Home Edition

Complete antivirus software for free

avast! antivirus Home Edition represents one of the best FREE antivirus protection currently available on the market. This edition is Free Of Charge for non-commercial & home use only. If you are not a home user or if you use your computer for business purposes, avast! offers a wide range of more suitable products providing higher data security, starting with avast! Professional Edition.

http://www.avast.com/eng/avast_4_home.html