XP pro sp3
32 bit
cpu Intel T2400
directX 9
2 Gig RAM
Nvidia GeForce Go 7400 256 mem
45 Gig free space

I read that this is above the minimum specs for the MB 7.5 version. The app crashes like a b*tch constantly. Especially in story mode. Searching on the web reveals quite few crash complaints related to motion builder in general, which is good for users but makes solving the problem for me harder. Also the app is incredibly slow in the viewport, even just with a simple skeleton on the grid.

Have the latest drivers.
Advice appreciated as this is an amazing bit of software and I would like to make more use of it.
Cheers

Well you have a WAY underpowered computer for 3d graohics. thats for sure. I mena the basic computer graphic artist (over here anyway) use have about 8 times more ram, 1000 times more diskspace and a way better gfx card.

But mostly the reason is your underpowered gfx card.