alk- I'm sure you'd know it if you had purchased the V8800 series card as they are quite pricey but they work. Do have to use the proper driver though which I had discovered in the readme files and downloaded.
Also, you really do need to switch to 64bit for 3D editing. Anyway, you are on the way to resolving the issues one at a time. When people ask me about editing 3D I tell them straight up, it can be done with normal editing computer, but if you want performance, be prepared to build the most robust and expensive system you have ever done. Right now the only crashes I get are when I allocate 7Gb of Dynamic Ram for shift B previews and then forget to reset it back to 0 when done, then I try to open a 4th instance of Vegas and then the system slows to a crawl. Still, I do save my project often but unlike before when I had 16Gb of C drive space and had to save every move as it would crash so often, now with the new Vertex 4 256Gb C drive, I save my work about once every 30 minutes or so.
I agree that the crash reports don't work too well but there are tools that can help you determine where the trouble is. One freebee I use here is: www.Moo0.com
system monitor. It's free and really helped me find where my bottlenecks in my computer were. I load it up and have it monitor in a right sidebar, every drive, ram CPU and app hitting the system at the moment. It's how I discovered my AV was causing about 25% increase in render time. It showed me that the C drive free space had reduced by 35Gb during a 7 minute iso file render. The version I use does not offer diagnostics on the graphics card. I understand they are working on that.