Many instances where my client will go black

There are many instances (such as now) where my client will randomly go black. I was in champ select and when it came time for me to choose, it made the noise and my client just went completely black. I've also had this happen when I get into matchmaking lobbies and my chat box is black. No one can see what I type and I can't see what they type. What's up with this? I now have a time penalty for dodging (thank goodness I chose to play a warm up game before ranked - I'm in my series).