I'll give that a go, I try and keep it a streamlined as possible when running maya just because of this..

All that was in my scene was a Poly sphere, a cube and a plane I was trying to explode the cube and dent the the sphere by using dynamics , with no particles, it was running it at decent playback speed and rendering quite fast so I was really shocked when this came up.

I'm wondering if theres something with windows cos this started to happen more and more (with different software, avid, borland c++ builder) unitll i re-installed windows