Weird Gmod Desktop Crash

Problem: I can play online on Garry’s Mod for about 10- 30 mins until something like this happens. Garry’s mod will freeze up momentarily, crash to desktop, but then STILL run in the background? Like, I can move my mouse and hear the menu and shoot and stuff. WTF? Not sure what is goin’ on here. Not a single error message. No dump, nothing, as the game is still technically running fine, I just can’t see anything but the desktop.

SPECS
EVGA GeForce 580 GTX
Intel i7
8GB RAM
125 SSD

Help?

This happens to me. I wonder what it is. Someone help me! It’s frustating to work at something in GMOD and then this happens. This usually (but rarely) happens on TF2, too.

Happened again today and I found out that it said nvdkllm or something like that had stopped working and recovered. Happened on TF2 also.