First post ever on the forums! Yay!
The UAC stands for User Account Control.
Basically, UAC virtualization makes it possible for users to run applications that normally require administrative access. It achieves this by creating (and storing) virtual copies of areas such as system32, program files or even registry areas such as HKLM\Software. So when an application requests access to those system protected areas, UAC virtualization redirects those requests to the virtualized versions located in the user's profile.
For more info check out:
http://www.windowsecurity.com/articles/Pro...tion-Part1.html
Hope that makes sense. I just started testing Windows 7 at work. I'll share some of the interesting things found in a later post.