Introducing Windows Live OneCare, the new all-in-one, always-on PC care service from Microsoft. It works quietly in the background on your computer, so you don't have to worry about nasty interruptions from viruses, spyware, hackers, and other unwanted intruders. It also goes beyond security, regularly backing up all your important files and cleaning up and tuning up your PC to help keep it running at top speed. Because you have better things to do with your computer.
http://onecare.live.com/purchase/default.aspx