Microsoft's OneCare Antivirus
Microsoft has an antivirus program in beta testing called OneCare. The latest update links OneCare with Windows Defender. In case you are not aware of this Windows Defender is Microsoft's new name for Microsoft AntiSpyware.
The two are now one and are still in testing as a beta. I do not believe a release date has been set but if you want to try it out you can get a copy from:
http://beta.windowsonecare.com/support/help.aspx?query=PROC_configure_spyware.htm
Have a great day!