Black Screen During Champ Select

When I enter champ select, my screen goes black. That's it, plain and simple. I can't select a champion or ban, so I get kicked out of champion select and receive a ban timer. I click on find match, I accept the match, and when I enter champion select, the screen goes black. This sucks because it's happened twice already. I've got a ban timer, and I can't even play the game. I strongly believe that this is not the fault of me or my pc, which is a nice way of saying fix your client.