After loading into a game, my computer will play the windows sound and the screen turns black.

This started happening to me the last couple of weeks, and has gotten me leaverbuster and lost me lp many times.

I will go through champ select and load into game just fine but when the game starts I hear the windows sound and my computer screen will go black. I have the ability to tab out, and I see the options when doing so. But when i "switch" the screen will stay black. My mouse also turns sluggish, and I can't move it properly.

Please help.