So I installed a beta version of W7 Ultimate and it's displaying a watermark that says "this is not a legit version". I never had a legitimate product key. I want to purchase a real version and upgrade appropriately. Can I purchase an Upgrade license to Windows 7 Ultimate or do I have to purchase a Full version? Also, what if I wanted to install Windows 7 Home Edition instead of the Ultimate version. If I did this, I assume I would have to install the Full version correct?