How to Upgrade my Mobo without changing my Windows

Solution
You can generally go from Intel to Intel, or AMD to AMD but usually not from one to the other due to driver issues. Reactivation by phone is usually all that is required.
custom built? I did a swap from a msi mobo to my asus sabertooth and everything worked fine, you will need to do all the chipset updates and you will not need to re enter your key or anything and even my raid still worked after the swap.

Id say give it a go in worst case you call kicrosoft and they will give you a new key since its just a mobo swap