Microsoft Security Essentials

http://www.microsoft.com/security_essentials/

Microsoft has officially released "Security Essentials" which replacing their very effective Windows Defender spyware protection and adds Anti-Virus protection.

It seems to be unobtrusive, and should be effective, with multiple updates per day. Absolutely Free.

We will be switching to this on all of our home machines, which, uhm, currently totals 5 machines running six Windows operating systems.

Is available for XP, Vista and Windows 7