Windows 10: Using Win 7 key in a new Win 10 install, impact on old machine

Googled this to death and cant find anyone asking the question .

I have an existing Win 7 Ultimate computer, and I've built a new Ryzen box and installed Win 10 Pro on it .

I wanted to try and use the key from Win 7 , to see if that will activate.

The only concern I have is if it does activate, will that cause the Win 7 machine to automatically deactivate.

I need the old machine to stay up and running cleanly for a while. Deactivation probably wouldn't hose it completely, but I'd rather not deal with that .

:)

 

Old Win 7 key - new Win 10 HDD install question ...

I paid retail for 3 copies - "Family Pack" - Win 7 Home Premium many years ago. They all 3 use the same install key. I am now finally getting around to investigating Win 10. Previously I only used two of the 3 as Win 7 and never actually activated
one of them. I just now have installed one of them for Win 10, which I installed via USB ISO on a new HDD. It activated perfectly. So with this install I'm trying out several very old graphics and CAD softwares for compatibility with 10. So far, so good.
Now, with surprising success using this old expensive professinal software on 10, I'd like to install another 10 on a somewhat newer machine and new HDD, but not as an ugrade to an existing install of 7 that was activated years ago. I do want to use one of
the three keys I paid for years ago. The drive/machine that the key was originally on is long gone and no longer used. Long story I know but what I am wondering is ... what to expect from MS when I try to activate a key that was first used so many years
ago??? Any clues how I might go about doing this? Many thanks!

 

How to get product key of old OS (Win 7) after upgrading to Win 10?


OK guys, this will take time, encoding in process but after that I need to do some basic editing and add explaining titles before I can post the video:




The process as I did it:

• Install Windows 8.1 Pro on a new machine, activate with a valid product key which had never been used before. A totally virgin key. Activation OK
• Reinstall 8.1 Pro on same machine wiping the HDD, use the same key to activate. Activation OK
• Reinstall 8.1 Pro on a new machine, use the same key to activate. Activation OK
• Upgrade the last install to Windows 10. Windows 10 activation OK
• Reinstall 8.1 Pro on a new machine trying to use the same retail product key, resulting this:

 

Fresh Install of Win 10 without Serial Key?

Looking to reformat a laptops HDD, and then reinstall Win 10 fresh. The problem is it came pre-installed with Win 8 and I did the free upgrade to Win 10. How exactly would I re-format the HDD, reinstall Win 10 and ensure it reactivates properly? I don't see a Win 8 serial key anywhere in the contents of the box.