OEM keys also rely upon a hardware string in the BIOS - this generally only applies to big box builder computers, such as if you buy a laptop from Dell, HP or whoever.
If you have a custom built PC then you'd need your own key. I don't think OEM's will activate on non OEM kit. Though, it's been many years since I've even needed a key, I just use Windows 10 and I keep shoving my old Windows 8 keys I bought at it (Got them for £15 each!) and it keeps working.
Though, ultimately, I want to get away from Windows, one day............ no more keys to ever have to worry about then!
