FreeSoftwareTools.net

avast! Home Edition is a free antivirus for non-commercial and home use only.

avast! antivirus Home Edition is free to use but you have to activate the program (within 60 days) by doing a free registration here.
After your free registration you will get a key valid for 1 year.
Some feautures are : anti-spyware built-in engine, anti-rootkit built-in engine, P2P and Instant Messaging shields, network shield, web shield and automatic updates