tribz and mongo have it. You don't need to worry about volume or OpenLicense keys, WGA, and all that crap if you do it correctly. Even if you have to call Microsoft activation, you'll be fine. Technically what you want to do is outside of licensing (depending upon who you ask at Microsoft,) but no biggie, just don't tell them that's what you're doing if you have to speak to someone. Just act stupid like you're reinstalling multiple times and activate each time. It works.