Wipe and reinstall. Then make a system image of your newly tweaked "properly licensed" system and your family member will love you for it. You can do it any way you choose, but you chose this forum to get its expert advice and members are telling you to reinstall. That alone should tell you something.
Actually, my relation's away for a few days, leaving his PC at my mercy I was thinking maybe I could do the downgrade to Professional and all the Post-SP1 updates, etc now and SLIC activate it (assuming I can find a Pro key), I'm sure that shouldn't be too hard!) and then when he gets his proper key, I can just flash the BIOS to stock and re-activate it with his key then. Does this sound OK? It's just that it would be good to do as much as possible whilst he doesn't need to use the PC.
OK, so you think changing the values in cversion.ini to 7600 rather than 7000 might work (and leave the registry values at 7100 or change them back to 7601)? I obviously couldn't modify the cversion.ini on the mounted ISO, so I just extracted all the files to a folder on the HDD and modified it there before running setup.exe. I can't see that would cause the upgrade option not to appear though.
OK, I'll revert to the unmodified cversion.ini and change the registry values back to 7601 (after trying 7600). Do you mean burn the iso to a DVD and try that? There's "available" updates as I have Windows set to notify but not download or install. The fact that there's updates available wouldn't prevent the upgrade option appearing though would it?
OK, I'll do that then and if it still doesn't work, trying burning the iso to a dvd. Oh yeah, that was one of the first things I did
That was the first thing you should have done was just burn the iso to make windows 7 dvd. At the of the day it is always good to have a copy in case you hard drive goes down and you lose archives. As for mounting it as a virtual drive what would happen if the upgrade needed to reset your computer you virtual drive would probably not be mounted and your upgrade or downgrade would fail because it could not find the needed drive or files.
Why would anyone downgrade from Ultimate to Professional ??? Just wondering Is Professional better in any way?
I believe the poster said somewhere in the thread that this person's PC was going to go from non-legit Windows to legit. So they evidently want to pay for Pro, not Ultimate.
That turned out to be all it was. Once I installed the updates, the next time I ran the Win7 Installer (from the folder on the HDD) the option to "Upgrade" to Professional appeared.