I have had this copy of Windows 7 for a few years and now I get an error message saying its not a valid copy of windows. I did buy a new product key for it about 6 months ago and its been working fine. I don't know why now its not valid. I tried activating and putting in the product key and they say its not valid. What should I do? I am sick of this nonsense. Do I need to buy another version of windows? Not sure I want windows 8 or not. since I have boot camp I need to buy the full version. Do you need to do a fresh install of can you upgrade over what I got? I never have problems with my Mac, just the windows side.. I need it for a few programs I run.