>>> I read other people had blue screen when they switched motherboard while using the same hard drive without reinstalling windows.
That must be true, then, if other people say so. Why are you asking other people ?
Look, there is no written guarantee.
Anyway, it's not really a good permanent solution, it's kind of messy and sometimes the Metro/New apps don't work any more. On second thoughts, I'm not even recommending it now. The only good thing about it is that it takes very little time.
I thought the alternative from the other guy was very time-consuming and very unlikely to succeed. You will spend hours first downloading an ISO for Windows 8, installing it, TRYING to activate it with your OEM key - good luck ! - then you would have to do the upgrade to Windows 8.1 which takes ages ...
So therefore, my advice is the same as before:
To have a properly activated Windows 8 or 8.1 on your new motherboard you will almost certainly HAVE to buy a new copy, OEM or retail. There are other solutions which we can't discuss here.
BTW, regarding 'other people' and blue screens. I have never seen a BSOD in Windows 8 yet, and I swap HDDs around all the time between motherboards, from ASUS, AsRock, Gigabyte with all sorts of chipsets from Intel and AMD.
I can't recall any occasion where Windows didn't boot up, although as I said, some of the apps no longer work, that also happens when you install a different video card.