I've been sitting on a copy of Windows 7 Ultimate for about 6 months since I have no use for it so I figure I might as well use it if I can by upgrading one of my HP or Pro machines, but will it even work?
Yes.
Windows Anytime Upgrade - How to
Save a backup image before and after you unlock the few extra expensive features in Ultimate as this will be the much easier way to recover either version.
You can always migrate the Ultimate elsewhere if you want. Having the Home Premium image makes this a lot easier.
Well, that worked surprisingly well :)
The entire upgrade process took less time than it usually takes to install Windows Updates every month. The only thing that irks me slightly is that it reset my Start Menu most frequently used programs list and it also kinda concatenated the Windows default pinned taskbar icons (IE, WMP, Windows Explorer) with my existing taskbar.
Oh, and for some reason it didn't automatically activate - I had to go to Control Panel -> System and manually reactivate...
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