Windows 10: Reinstalling windows 10 pro and no physical key - Should I buy new serial key?

In 2015s I forgot when exactly I buy this bought windows 7 professional 64 bit, and when windows 10 was released I use the free upgrade to upgrade my windows. I have not reinstalled my windows since that and my hardware motherboard, processors, vga almost stayed the same. But recently I started to replace some the old hardware because either they were too old or have technical glitches in October 2021 to be exact. I replaced my VG with ATI Radeon RX 560 4GB without reinstalling the windows, just reinstall the driver. For old games which had the option using dx 11 or dx 12, I experienced

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windows 10 key

Thanks but I don't want to do any decrypting. I want to download a Win 10 ISO from Microsoft and install it using my Win 8 key. No other steps required. Is that possible?

 

Installing Windows 10 using Windows 7 key

Two quick ways to use your Windows 7 key during the install:

1. When asked for the serial #, put in that Windows 7 serial # and continue on. It should activate as soon as it hits an internet connection.

2. When asked for the serial #, at bottom of window click on the I don't have a serial # text (or whatever it says). It will then ask what version you want to install, ie. Home or Pro. Be sure to install the right version that matches your Windows 7 key. Then once you get into windows you can activate by putting in the key. Some people prefer this method, not sure why honestly. Easier to do #1, since the installer will see your key and know which flavor of Windows 10 you are trying to install.

 

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.