Product Key question

I never fully read up on the way this works. I have both a Windows 7 OEM disk and a Windows 8 OEM disk. What does OEM mean compared to the 'full' purchase? Is it just missing support from Microsoft?

Also if I buy an OEM Windows 10 disk, will I be able to reinstall it as many times as I want? I have read that Windows 10 ties its key to the hardware, so if I want to change computers will it be difficult? I reinstall windows quite often and I am wondering if Windows 10 will be able to do that.

If you make a significant hardware change then you will have to call the Microsoft support and have it re-sync the key. I've had to do this each time I get a new GPU. And no this process is not hard. Its all automated and take ~10 minutes.


So as long as I have the original product key I can install it on any computer, and it just invalidates the other installs, like it does with the other versions of windows?


OEM is tied to the motherboard only, correct me if I'm wrong. Is there still a points system for upgraded parts for a re-verify or was that never a thing?
memory I would assume to be "free" but ...You know what, Google is a thing.

I personally wouldn't buy a Windows 10 OEM disk but whatever.