Finding windows product key

A Mean Vampire

Honorable
Sep 1, 2012
4
0
10,510
I put this here because windows 10 was the last OS I had on my laptop. the motherboard failed, I got financial aid, and I have a new motherboard on the way today. I had thought that it came with a sticker of the product key on the bottom of the laptop but it did not (came with windows 8, than i upgraded to 8.1 then to 10). I currently have the hard drive plugged in to this computer that im on now, but don't know how to retrieve the product key as I can't boot from it and check.

Ive tried a few programs, is it even possible to recover the old windows 8 or 8.1 key since it was last running windows 10? I might just try and see if it works without having to do a clean install but im not crossing my fingers.