I am really chuffed with this. This looks an excellent product and will be great to get installed on your home Computers, plus it is Windows 7 Compatible too !.
Some of its Key features are ;
Comprehensive malware protection
- Simple, free download*
- Automatic updates
- Easy to install
So go ahead and download it from here http://www.microsoft.com/security_essentials/

I just encountered a virus that took MSE down cold. It was a fake antivirus scanner that loaded through an infected webpage. As soon as I clicked on the link, IE was redirected, then MSE was terminated, and a window popped up saying "your computer is infected by a Virus scan now?". No matter what you click it begins a fake scan during which it infects all windows files, Including the task manager. Making removal difficult. Any attempt to use windows explorer or a malware scan, or task manager, or system restore is blocked by the message this file is infected! The only way I have been able to remove it is to reboot in safe mode, open task manager as windows is booting, then end task all unrecognized tasks that load until I am able to start system restore. All malware removal programs that I tried to use Norton, MSE failed to remove it.