Windows 10: I have an old not-in use laptop with win7 product key. Can I use the product key for new pc?

I have an old not-in use laptop with win7 product key. Can I use the product key for new pc?

:)

 

Product key association disable on old pc

Hey,


I sold my old pc to a friend. He installed some missing parts (HDD, GPU and RAM). Then we installed Windows 10 Home 64-bit version from USB stick. I was surprised to see that windows was automatically activated after that. I did some digging and found out that it is using my product key, which i use now in my own new pc. My friend does not have his own product key, the idea was that he just uses the unactivated windows with limited features.


I uninstalled my Windows 10 product key via command prompt in friends computer (as i understand this is only local solution, if he reinstall windows or clicks the active button, it reactivates automatically with my product key) and now it says windows is not activated, but my product key is still shown with Produkey app in his pc. So far windows is still activated my own pc.


My questions:

1. Is this all i need to do?
2. How do i get rid of product key showing still with product key showing apps on my friend's computer?
3. Is there a way to get rid of association of my product key on that old pc that i sold to friend?

EDIT: I originally installed windows 10 via upgrade option from Windows 7, if that matters.

 

Product Key from old laptop

So it seems my new laptops windows isn't genuine. I thought about buying a new copy of windows but then remembered I have this old laptop with its product key still available (but the laptop is demolished), cant I use the product key of the old laptop
to activate windows on my new laptop?

 

Win7 Product Key problems

Corrupted files on my system disc meant I had to re-install Win7.

I have used the product key originally sent to me when I downloaded Win7 (I also bought physical media) but it now says "invalid product key". Download and licence was purchase via Digital River.

Suggestions?