whateverdude :
Dude i'm sorry if you want to remain in your ignorance it's fine by me.
I explained you in plain English that you cannot change MB if you upgrade for free to Windows 10 because the the number of times you can reactivate Windows are zero zip null.
I believe you are mistaken and should be listening to these others here who know what they are talking about, because I just upgraded from the Gigabyte Z170x-Gaming 5, TODAY, to the ASUS Maximus VIII Hero, and while for some reason, it would not re-activate through my Microsoft account, which it has done previously, all I actually had to do to bring my digital entitlement back into effect was enter my old Windows 8.1 key by clicking the Change key option. Poof. Magic.
Additionally though, I've reactivated at least fifteen other systems, if not more, after changing motherboards or moving the hard drive to an entirely new machine, and ALL of them had been upgraded to Windows 10 from older versions of Windows. None of them required buying a new license, but they all required either having a Microsoft account tied to that Windows digital entitlement, entering the original product key from the qualifying product or going through the Microsoft activation protocols. That should be plain enough for anybody, even in English.