I turned on my computer for the first time in a few days today and got a "Windows Activation: An unauthorized change was made to Windows. -- Windows has discovered a change that will result in limited Windows functionality. Use the link below to find out how to fix Windows." Clicking "Close" logs me out and "Learn more online" led me to a "Genuine Microsoft Software" tab that has a "Windows validation in process" that seems to go on far longer than "This may take a few minutes, do not navigate away from this page." A secondary pop-up states "Windows Activation: An unauthorized change was made to Windows. -- You will no longer receive notifications, including those about your license or activation. Use the link below to find out how to fix your system." (and the suggested link is "Learn more online" which goes to the "Genuine Microsoft Software" tab. My computer runs on Windows Vista (don't know which version). Any suggestions on a possible solution?