Client Spontaneously Closed

I just got an AFK warning for leaving in bot games (??) and as such have a wait time to enter a game. However, after this timer expired and the queue popped, giving me a game, I loaded into champ select. Where everyone's names should be and the chat/champions, all blank screens. This sometimes happens when my computer runs slowly, so I type jg and then wait. After no more than two seconds, the client closes and I get a notification ding from my computer but there's nothing there to have made the noise.