Random black screen with cursor

Hi.
I have a problem I hope someone can help me out with.

My Asus computer randomly started to get black screen this happens when I for an example sit on facebook and maybe play some game.

After like 10 minutes a spot on the screen starts to turn black and when I move the cursor around its kinda "painting" the rest of the screen and it will all go black. I can let it stay for hours and it wont come back.

I have to manually kill the computer by pushing the turn on button for a few seconds.


Any suggestions ? please