What I was trying to say was this... From my understanding of how it works, Interlok, (the piracy protection/registration tool) writes out a code block to your disk when you register. If this is on the same drive as your OS, and your drives are swappable, one with P5 one without, you'll be fine. But... If you have two identical OS drives, (C:) and P5 is installed to a different drive, (D:) then P5 may only work when the OS drive you were using when you installed P5 is installed. No control block, no poser5. Think of it as a two part key you need the app and the control block to function. later jb