Ok, after reading a post by mariner here, and some fiddling, I SEEM to have fixed my problem.

I added a profile for Poser 7 in the nvidia control panel, under "Manage 3d Settings>Program Settings". The only thing I changed from the global settings was turning the "threaded optimization"  OFF. Turning it ON seemed to preserve stability as well, however, camera tracking was VERY slow and choppy, and my cpu usage never dropped below 50%... Turning it OFF, on the other hand returned poser to it's normal smooth operation.

I opened and played around with about a dozen different scenes and it hasn't crashed yet.

Hope this helps somebody.