Really, the only thing I'm going to need to build a new Virtual PC is the Virtual PC software itself. You, too, can get a copy of that software right here:
http://www.microsoft.com/downloads/details.aspx?FamilyId=04D26402-3199-48A3-AFA2-2DC0B40A73B6&displaylang=en
Oh, and once you get that downloaded and installed, you might want a copy of an OS. For my example, I'm going with Windows 7. You can get your own copy of that here:
Microsoft Windows 7 Ultimate
After that, everything else is an application, and follows the same steps to load as the OS. I love that about the virtual PCs. :)