In case this help, I keep this text file for when I do mother board upgrades(no need when only CPU on same chipset):
Also, Windows 10 and 11 are awesome when you use the same system disk after upgrading, at first boot it takes a while, but Windows will install the drivers needed, and then you can use RAPR(DriverStoreExplorer) to delete the old ones.
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So below are the steps to remove activation key from the system:
Log in to the system with admin account and open CMD with Run as admin rights.
slmgr /upk It stands for
uninstall product key. The /upk parameter uninstalls the product key of the current Windows edition. Once this command will execute
you need to restart, the system will be in an Unlicensed state unless a new product key is installed.
Then go to your Online Micrsoft account and then remove the device from your account:
https://account.microsoft.com/devices
Once all done above, you can see your Windows actvation properties status as not available.
Build your new system.
Enter your key in Windows.