I have multiple license keys for Parallels going back to Version 4. The computers have all died long ago. I need to figure how how to deactivate the old licenses so they can be used on different computers. There does not appear to be a method to do this, or even see what computers are licensed to what version for that matter. Specifically, I need to deactivate all licensed computer for my Parallels 8 installation so I can install it on a Yosemite laptop as this is the only version that will work for this OS. Could you please explain the procedure. Thanks.