How to restart nVidia CUDA driver without restarting?

I'm using Ubuntu right now and I want to restart the nVidia CUDA driver installed on my system since it has crashed because of some unknown reasons. Is there a way I can reset the nVidia CUDA without reboot because I haven't saved any of my documents. My computer is hanged and I don't know what to do. I might restart this time but from next time, what should I do?