Super9ova :
Colif :
Can you right click this PC on desktop and choose properties from the menu
in next window, at bottom there is a section called activation. There should be a way to contact Microsoft from here, and they might be able to sort it out for you.
Not a great difference between retail and OEM now.
I will try this, but it was a cheap copy and could be a volume key so idk
With licensed software, especially a Windows OS, 'cheap' is very often not 'valid'.
The install and the license are two different things.
Where did the install come from? If not from Microsoft, I recommend you obtain a valid license, and do a full reinstall.
If you got the Win 10 install directly from MS, and your 'cheap key' did not activate, then yes, you can just buy a real OS license, and activate the current install with that.