I bought Windows 7 Pro during the student sale, and there was lots of talk about MS supplying the Full version, even though it was advertised as the Upgrade version. So I've got this Win 7 Pro key, and I'm wondering if the PID Key Checker that's out there will tell me if it's an UPGRADE version. Right now it just says "Retail" Is it possible that it's the retail upgrade version? Or is it the full retail version? I don't have a blank drive handy to install it and find out. Thanks!