Windows 10: Reinstalling windows 7/upgrading to 10

I have an old computer with Windows 7 Home Premium. Its quality has degraded over the years, and recently ran into some bigger problems, therefore, I would like a fresh start. I want to upgrade to Windows 10, but I understand that Windows would no longer be activated because the period to get a free upgrade ended. I would still like to get Windows 10 on it, but I can settle for Windows 7 for now. How do I reset/reinstall windows without losing the key?

:)

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Will windows 10 still accept the license keys from 7 and 8 now if I reinstall my computer?

Does Microsoft keep a list of users who upgraded to Win 10 using their 7 and 8 keys so that when users need to reinstall windows 10 the old keys would work?

Do I need to call in Microsoft to ask them to activate my Windows 10 when I give them my win 7 keys?

Both computers are laptops. The windows 7 machine had the serial printed on the back, and I needed to enter that when I upgraded to 10. The windows 8 machine had the serial built in inside its boot system so I didn't need to enter the key when I upgraded to 10, but I did manage to write down the keys using a fetcher program.

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Yes, still work, no need to call, just be sure to have internet access when you start to install 10, I work at pc shop and did this few days ago, used a key of 7 to put clean 10(wasn't used for upgrade).

 

How to reinstall Windows 10 if my computers used the free upgrade from 7 and 8?

Your ild keys should work but if you registered the key to your online ms persona (email address) it should be tied to your account , install without a key login with your credentials , then activate.