Free antivirus software for non-commercial home use (complete desktop security)
Edit By BS Editor: avast! 4 Home Edition is a free and complete ICSA certified antivirus, with Checkmark certified anti-spyware, and cutting edge GMER anti-rootkit software for non-commercial home use.
avast! continues to achieve Virus Bulletin VB100% awards, with an uninterrupted record of wins for over two years, which not all competitors can claim.

avast! Home Edition includes the following components:

On Demand Scanner - with Skinnable Simple Interface - just select what you want to scan, in which way, and press the Play button.

On-Access Scanner - with special providers to protect:
most available E-mail clients,
Instant Messaging - ICQ, Miranda etc.,
Network traffic - Intrusion Setection,
P2P protection for Kazza, BitTorrent etc.,
NNTP Scanner - scans all Usenet Newsgroup traffic
and of course all operations on PC files.

avast! can scan inside the huge number of different packers including ZIP, ARJ, RAR etc. even Outlook Express .dbx files.

Boot-Time Scanner - scans disks in the same way and in the same time as Windows CHKDSK does (on NT/2000/XP only).
Screen Saver Scanner - scans PC during your coffee breaks.
Virus Chest - safe, isolated folder to store Infected, suspicious and even some system files - to restore them.

True incremental updates mean that, unlike some other antivirus solutions, automatic updates are small and therefore quick to download - and most updates never require a system restart: so just set the program to automatically keep you up-to-date, and the it just works.

avast! 4 Home is available in English, French, German, Italian, Japaneese, Polish, Portuguese, Russian, Spanish... altogether around 30 languages. you can free download avast! 4 Home Edition 4.6 now.