For the past couple of months New Vegas has been crashing/freezing my whole computer and the only way to recover is to restart completely.
After playing for a few minutes the entire screen goes black, the sound loops and my monitor says something similar to "no display" (can't remember right now.) And the only way to fix it is to restart completely.
I formatted my computer and did a fresh install, and it still continued to crash. I installed Far Cry 2 and it did the same thing. I then thought it was a bad video card. But, I ran a video card stress test (FurMark) and it ran just fine, with no crashes.
I then realized BOTH games put their game saves on my C: drive (a Crucial M4 120GB SSD). Since there was no way to change my save games directory (that I know of) I installed Link Shell Extension (http://schinagl.priv.at/nt/hardlinkshellext/linkshellextension.html) and created a symbolic link of my game saves folder on another hard drive.
Ever since I did that Fallout: New Vegas hasn't crashed.
So, I can't promise 100% that this will be your fix. But if you have similar issues with black screen crashes, and you have an SSD, I would recommend moving your game save folders with a symbolic link.
I have no idea why this happens, there are no other problems with my SSD. =\
Hope that helps!
- oduska