How do I change motherboards?

Alright, the subject title might have been misleading. I belive I get the idea of how to change the hardware on motherboards: taking off heatsinks, removing RAM, re-applying thermal paste, blah blah blah. 

However I am very much concerned about my OS, I use win7 home premium x64, and am determined to keep it.

If I were to switch motherboards what would I need to do to get windows working again. Would I need to reinstall it? I could live with that easily enough, however could there be any issues with copy protection? 

Anything you say could help me, as I am a complete N00B to building PCs. Tech specs below.

 

Switching from:Gigabyte GA-A55M-DS2 Micro ATX FM1 Motherboard

switching to:  ASRock A75 PRO4-M (Allthough if anyone can find somthing more futureproof in the same sort of price range, with same socket, RAM, and capable of supporting a radeon GPU that can crossfire with a 6550, I'm all ears.)

Any help you could provide would be great ~~~

 

Before taking out your gigabyte motherboard Uninstall all the drivers related to it (Sound, LAN, Etc.) Then install your new motherboard install the correct drivers for you new motherboard and you should be set to go! However if windows thinks you switched switched computers just contact microsoft about it and they will get it dealt with, Tell them you just got a new motherboard and they should fix it for you :D 

Thanks for your help. I appriciate it .Z