Greenborder is virtual machine software that makes it difficult for spyware and hijackers to get access to your system. Google may roll out a free version of this product soon.
http://blogs.zdnet.com/micro-markets/?p=1454
Why did Google buy it?
Interesting point:
"Unlike virtualization software from rivals requiring multiple Windows licenses for each corporate user, GreenBorder insulates the Microsoft Windows system from the underlying computer hardware and only requires a single license for Windows, according to Neil MacDonald."