You may install Poser 3 times on one machine, 3 machines, or any combination thereof. My God, what about the fourth time? Actually, we have a couple of customers who for one reason or another have had to exceed 3 installations, usually due to upgrades, viruses, etc. What happens? A flag pops up saying "You have exceeded the maximum number of installations". You call Customer Service, verify your registration information, and get your installation counter reset. The whole process takes 90 seconds. Easy? Simple.