Windows 10: My Windows Product Key Won't Activate on My New PC

Hi, I bought a Windows 7 CD that comes with the product key and have been using it without problem for 10+ years.I just built a new PC and connected my SSD with the Windows installed Windows 10 - free upgrade from the product key I own with Win 7 purchase. Now it says to "activate" again and I do not have the product key.. How can I resolve this issue? I assume if you can look my Microsoft account, you can look into it and confirm my product key there. Please let me know if there's anything you need to further look into this.

:)

 

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.

 

Windows 10 product keys and activation - and the KMS angle

Changing the product key to the generic Windows 10 product key will reset activation to the standard retail channel for activation. It might just activate (if there was a previous digital license for Windows 10 for that computer established with Microsoft). Once Windows 10 is back on the retail activation channel, then more than likely changing the product key to the Windows 8 product key using the same method may work.

 

Windows 10 will not activate Error code 0x803F7001

thanks
I activated my Windows 10 from product key Windows 7