I have a copy of Vista, and I also have an Upgrade Edition of Windows 7 Ultimate. It would be a pity to waste the Vista license just so I can use Windows 7 in Bootcamp, and I want to avoid it if necessary. I have a previous copy of Windows, so this isn't against the forum rules is it? If it is, mods then close this thread! I've heard of clean installs with the upgrade disc and modifying the registry key OOBEInstall, but how would I go about doing this through Bootcamp? Apparently another method involves not entering a product key, and then installing Windows on top of itself again with a product key, then it upgrades from itself? Is this possible in Bootcamp? Previously all you had to do was insert the old OS disc and the upgrade disc would work! PS: My MacBook Pro Early 2011 with Lion & Bootcamp 4.0 doesn't support Vista, so I can't put that on anyway!