I have a question about installing windows 7 multiple times. Right now I have a mobo that is linked to a system builder version of windows 7 I bought to save a little money. Now that I have a new motherboard to take advantage of overclock ing, I am wondering if I could by a license key of windows 7 off of a reputable ebay retailer and use the disk that came with my first windows 7 to install it? Do I had to buy a whole new cd+key or can I just get a new key? Any reply is appreciated thanks.