Crashing during game, then when trying to load back in.

Today was a normal day. Played several games, and then all of a sudden during an ARAM it freezes, then crashes. "Okay this happens sometimes." Try to load back in crash at 89%. Close and reopen. "Oh repair files." Okay... Reconnect to game CRASH AT 89%.... its been doing this for 3 days now. I'll play a few games fine then one game it just refuses to load into or crashes in the middle. I'm getting reported for leaving when its not my fault. I don't know what the hell is wrong with it, but repairing the files doesn't do anything. I don't know what to do. I've tried reinstalling ive tried the firewall. Nothing is working and it won't even let me "Report Bud splat" at when it crashes either. I have no clue what the hell is going on but I'm starting to get upset.