[Bob12]

I bought the family pack of Windows 7 and one of the computers I was upgrading had Vista Ultimate on it. Certainly not a "blank HD, unused PC", but the upgrade disk forced a custom install since I was going from Ultimate to Home Premium. It worked without a hitch. Of course, I have to reinstall all my software since the install of 7 did wipe the hard drive, but all my datafiles were on a second hard drive which wasn't touched, so reinstalling the programs shouldn't be that much of an issue.