I'm building a computer with 8 GB of RAM, so I need to get a 64-bit OS. I've already made sure all my hardware supports it. I figure since I might as well use Windows Vista for the first time, also. I've had many installs of Windows XP SP2, but never installed Vista myself. I was going to buy the CD (and Product Key) from http://www.newegg.com/Product/Product.aspx?Item=N82E16832116478 ... but I wondered how many times that Product Key would work before I would have to buy a new one. Please help if you've ever bought Vista or dealt with the verification process. Many thanks.