I might have made a mistake, in that I bought an Anytime Upgrade of Win7 Home Premium to Windows 7 Ultimate for a Windows 7 Pro computer. I have tried a few times inserting the supplied key, but errors pop up saying:
"The upgrade key is not valid. Please check the key and try again."
The computer is up to date. But I also know that MS has had problems in the past with the Anytime Upgrade and compatibility too.