Looks like I might try a reflect 8.1 image to a spare HDD, capture the product key etc and see where that leads me. The original MS package has a 32 bit and a 64 bit DVD inside. The w10 rtm version is an upgrade from W8/W8.1. I would recommend just a separate partition on a HDD for the Windows 7/8/8.1 activation then just go back to the original Windows 10 and activate that.Thanks for that. If you try to activate with a Windows 7/8/8.1 product key and you get a return that says the product key is in use on another computer, then you will have to install a copy of 7/8/8.1 on the new motherboard, activate that via the phone activation line, then you can use the same product key to activate Windows 10. I would recommend just a separate partition on a HDD for the Windows 7/8/8.1 activation then just go back to the original Windows 10 and activate that.

Obviously the product key will have to be for a matching edition/version (IE: home or pro, regular Windows, 'N' Windows or Single Language). Or it can be a Windows 10 retail product key. The product key can be a Windows 7/8/8.1 retail product key - if it has not been blocked from automatic internet activation by Microsoft. In order to activate Windows 10 on the new motherboard you will need a product key to enter. You cannot transfer the Windows 10 activation to the new motherboard (unless you can convince Microsoft to do it over the phone).

Change motherboard system image