To solve most unexplained crashes, this is what i do:

1- Start -> Run -> type "msconfig" -> go to "Startup" tab, and uncheck all things you absolutely know that you don't need to startup when your windows starts. In doubt, leave it there (although it can be re-checked if you lack a functionality in some other software). Then, restart and open your software directly (poser, daz, carrara, bryce...) and 50% of the crashes are resolved.

2- Get the DownRezer poser utility (small software available at renderosity), and use it to be able to put more people and clothing in a scene without charging your RAM. Although some people recommend the use of virtual memory, which works fine, it will still slow down your render time. Less RAM used = faster and more stable render, at every level. You shoud DownRez your textures on models too far from the camera to make a difference. 99% of the time, you can't even see the difference in textures unless you move the camera to a model big closeup.

3- Before a serious render, i restart the computer, which now has less stuff that auto-loads, and i do NOTHING else before i render, not even play in the software for adjustments. I do 20 hour renders with complex and polygon heavy files without any problem, now that i lower the system background tasks and DownRez my textures.

I'm a dork, animating dorks: www.TheDorkers.com