My friend built me a computer a year ago and since then he's kept my windows disk but lost the windows key.how could I upgrade my computer without reinstalling windows 7? Or a way that doesn't use the cd key. That's my only issue that I know of. But there's one last problem. He builds computers for a living and the windows disk he gave me might not be the exact windows disk he used for my computer. Will this effect me at all? Thanks!