Is the Windows 7 activated?
Copy the utility gatherosstate.exe on your desktop and right-click and Run as Administrator. You should see the GenuineTicket.xml on your desktop. In case your USB installer is not working properly, download the ISO from here and create the USB installer again. These ISOs can install both Home and Pro versions, depending on your previous Windows version. If you boot with the USB installer to clean-install Windows 10, click Skip when asked for a serial and then select Windows 10 Home if you have Windows 7 Starter or Home Basic or Home Premium. If you have Windows 7 Professional or Ultimate, select Window 10 Pro instead. Download any drivers before you install Windows 10, so you won't have any problem if you cannot connect to the internet.
When i was at Windows 7 SP1 base nothing would work. Neither the windows update of windows 7, the tool to upgrade to windows 10 or the USB i created from a different windows machine to "upgrade a different PC" worked at this point.
I set windows 7 to check for updates and came back 12 hours later. It had finally done something (nice one MS)
4 hours later my windows 7 machine is now fully updated.
I goto the MS website for updating to Windows 10 (I really dont know why i didnt leave it at Win7 at this point) and start the tool to upgrade the PC i am on.
I am not expecting to have to enter a windows key during upgrade, and i did not get asked for one.
After many hours of it telling me its installing, updating and then messages like "this wont take long" i finally have a windows 10 machine. Yahooo.......or so i thought.
No sound, hmmm thats funny, its an upgrade not a fresh install, where did my driver go ?
OK, download latest driver for sound on motherboard (as i have done before when installing windows7), install driver, middle of install Windows10 crashes on me, and it will not recover.
In i go again into another endless loop of reboot followed by a message basically telling me theres something wrong, maybe a reboot might help. No repair option in windows 10 ?
So, i decide a clean install option is the way to go. WIN10 USB inserted, start over, fresh install, asks for windows key, enter key, not a valid key.
Hang on, i just upgraded from windows 7 to windows 10, at what point does my key get upgraded ? surely at the point of the win10 install finishing ?
If Windows 10 was activated before you did the clean-install, you can click Skip when you are asked for the key. Just make sure you select the correct version Home or Pro, if you are asked and then continue. Windows 10 should activate again when online.
You shouldn't need a product key. Just click skip. If you try to upgrade and you get this message, then you are probably using the wrong Windows 10 version.
HERE (other thread).
In my case nothing would happen beyond a certain point; a "manual" upgrade of older drivers (SATA & PCI-bridge) helped.
Why is MS being deliberately a pain in the butt over all this ?
Distinct lack of information from MS during upgrade and fresh install.
I ended the matter by purchasing a FULL VERSION of Windows 10 and using the key on a fresh install. I did this because i will need to replace the motherboard/CPU/Memory on this computer in a few months anyway.
Thanks to all those who tried to help, and apologies if i came across angry or aggressive in any way, but this is a joke from MS, but it seems people are just willing to run with it.
After that one you may do as many clean installs as you like ...
Product keys are attached to the motherboard-ID is one more thing they found out: You can replace memory, hard disks etc. but only get in trouble after swapping the motherboard.
"Product keys are attached to the motherboard-ID" This is for OEM only though right ? Full version you can still switch hardware ?