I have read a lot about Windows 7 and am really excited about it. I would like to install it on my Windows XP Dell Inspiron 1150. The Upgrade assitant (or whatever it's called) told me I met minimum requirements. I know I am elegible for the cheaper Upgrade version, but what I can't understand is this: How does it know if I have XP or not? I am planning on buying it at Amazon. Do I need to send them some sort of proof that I own Windows XP? Or, when I run the installation, will it read into the reigstry or something like that and see my kernel is Windows XP and thus applicable for the upgrade? I don't want to pay up 120$ just to have the upgrade not work. So can anyone please help me?