So I an replacing my current motherboard and CPU with a z87 Killer from asrock and a intel core i7-4700k CPU. I am wondering if I will have to re install windows 8?, and how would I go about re installing it? Would I have to buy it again or what would I have to do to re activate it, would my old CD key I used to first activate it on my current motherboard work? It did not come with a CD by the way. Just a product key on a sticker on the side of my PC. If someone could help me out it would be much appreciated. This is my first time swapping my motherboard/CPU