I can't seem to find a way to upgrade my laptop Windows 8.1 (64 bits) OS to Windows 8.1 Pro. I do have a key for the new version but when I input it in the Windows updater, it tells me:
This key won't work. Check it and try again, or try a different key.
I'm using my MSDN and I know nobody used those keys.
To enter the key, I go to Control Panel - System, I see Windows Edition as 8.1. I click on "Get more features with a new edition of Windows" link, and in the popup "Add features to Windows 8.1" I select "I already have a product key".
Should I maybe just download the entire Wind 8.1 Pro ISO and run the install instead? I would imagine the Windows Upgrade Tool would do it in a cleaner way.