I know this is really basic, but one person has told me doing this will potentially really mess up the laptop. My question: can I change this from a 64bit Vista OS to WinXPPro or even Win7? Next question, if not, then what about partitioning and making the second partition OS one of those? I've always liked WinXPPro and it works well with some of my older things that won't work in newer OS's. But maybe I need to get into Win7 anyway. Thanks.