This is the link for Windows versions previous to 7:
http://www.microsoft.com/windows/vir...l-pc-2007.aspx
As Dosraider said, if you have a Home edition of Windows you may see a disclaimer about not being supported, but discard it and the program works all the same.
I'm quite mad at MSFT because what they've done to us Vista license holders. Windows 7 has only very minor changes (its internal version number is 6.1.x instead of 7.x), it could have been a SP for Vista, but they decided to declare a new version as a publicity stunt, because Vista was hugely unpopular for no reason. All that is OK, but now not only are we barred from the GUI improvements in 7, we're also left in the dark with the new virtualization tools, and we have to make do with the legacy ones. It would have been no effort on their part to make the same program available for other versions, at least Vista which has the exact same architecture. Not doing so is their best excuse for 7 being a whole new version, and yet an outrageous insult to the people who put their money on Vista, which is their product that they sold to us, but they've spurned it.