As of a few days ago this started happening. When im in a server on a selection menu my game will just go black and stop me seeing anything. I can move my mouse into the bottom corner of the screen and i can hear the click sound when i select a button, just can see whats on the screen. I can easily tab out of the game and close it on the ctrl-at-del menu, but to solve it i need to restart my PC.

This seems to be happening 2-3 times in a night. Any advice much appreciated.