Just uograded from Parallels for MAc from Ver 3 to Ver 4. Have received e-mail with activation Key. Product installed with no problems. When I enter the activation key, it gives me the message that the key is invalid. I have check the o's and 0's and entered either way. Still tells me that the key is invalid. I have(had before the upgrade) a valid copy of version three that I have been using for over a year with XPPro service pack. Any idea where I go from here