Hi InverseTelecine, I'm using Maya 2008 with SP1 - I just reinstalled last week so it's a clean install. If I create a new scene, then a ball and then gravity I can play it and the ball falls as it should. But, if I then create a cube, and 'duplicate special' it so I have about 100 cubes, when I play it Maya freezes for a few minutes and then plays the animation but nothing moves. I do have an old PC - it's about 3 years old and only 1/2 Gig of RAM. I thought this was the problem.