Installation was a breeze, here are the step-by-step procedure for installation. Update: Microsoft Security Essentials has finally been released to the public, check it out here. Below is the complete review along with some interesting findings.
I tested it on Windows Vista and was quite impressed with it. We were lucky to gets hands on the pre-beta build version of Security Essentials. It is already being tested internally at Microsoft and is rumored to launch in September of this year. Microsoft Security Essentials is the name of Microsoft’s latest Anti-Virus/Anti-Spyware software for Windows operating system.