Modern motherboard design
Modern motherboard design
No additional installation of Windows is required during the replacement of the motherboard.
Save all your files to another hard drive or Google Drive. Steam may re-download your games. Music fits on most flash drives or Google Drive as well. Don’t forget to turn off your old Windows key (ask @Syntaxvgm for guidance) so you can reinstall Windows with the previous key.
It seems you're experiencing some issues with switching items. You might want to try reinstalling the mobos for a fresh start.
Everything should function properly, though Windows will be turned off. You'll need to re-enable your product key. Occasionally the key fails, so contact Microsoft for assistance. I've handled this situation before.
AIUI :- The situation is that the key is tied to the motherboard BUT it is not really the MoBo itself that the key is tied to it is the controller on the MoBo, often the same controller is used on three or four MoBos so you may well 'get away' with not re-installing.n Personaly I would do the full backup before attempting anything just in case, and the full reinstall just to get rid of any rubbish your system may have accumulated. This is also a good opportunity to check you have the latest drivers, all the updates etc.
I've never had to replace a motherboard and get it to run smoothly without reinstalling Windows. No need to boot into Windows or worry about the old key. Just make sure you deactivate it so it can be separated from the old board before installing the new one.