A few months ago, i heard about the student Windows 7 Upgrade deal, and decided to take advantage of it. I had Vista Home Premium 32-bit and tried to upgrade to 7 Home Premium 32-bit, but it didn't work properly. I downloaded the upgrade and tried to install it, but before it finished installing, it said that the installation was unsuccessful and it was going to roll back to Vista. but it had already removed vista. my computer was stuck in a reboot loop, and didn't have vista or 7. I managed to fix this by getting a cracked copy of 7 Ultimate from a friend, booting from the disc, formatting my hard drive, and doing a clean install.

This copy of 7 Ultimate has been working perfectly for months, but a couple days ago, it started telling me that it is not a genuine copy of windows and i need to validate it. I traced this back to a specific windows update, and tried uninstalling it, and restoring to a point before this update, but it hasn't fixed it. (i realize now that i should have turned off automatic updates and screened all the updates).

So i need some advice on the best/cheapest way to fix this and get a legitimate, activated version of 7 on my computer. I have a product key for a Windows 7 Home Premium Upgrade from the original student deal, but no disc to install it from. If i can get a hold of a disc, will i be able to "upgrade" from this un-activated version of 7 Ultimate to 7 Home Premium and use my product key? Is it possible to "upgrade" from Ultimate to Home Premium? Or will i need to do a clean install? and if i do a clean install with upgrade media, will i be able to activate it? my last resort is buying a full version of 7.

I would really appreciate any advice you can give me. Thanks a lot.