I know that if you buy a new PC right now you are supposed to get Windows 7 for free once it is released in the Fall. Now I have a stupid question about that. I am assuming they will either mail you a disc(s) with Windows 7 on it or you can download it from Microsoft's web-site. Now when you load the new operating system onto our PC do all the Vista files disappear or will some be left behind?? I am only asking this because I am questioning the performance of a computer that has had two operating systems on it at different times. Will the computer be slower??? I always heard that Vista is a resource hog and the thought of downloading a new operating system onto the computer scares me. I have to buy a PC for school and don't want it to be super slow!!