Crashes my PC as soon as getting into a game.

Hello all. IEatUnicorns here. I've been having a bug that has affected my league of legends greatly. Not only can I not play the game, but I have gotten a leaver buster of 20 minutes for it. The bug that is happening, is that everything is all good up until I get into the game. After around 2-5 seconds, my entire computer crashes, and I have to restart it. I have looked everywhere all over the forums, and tried to fix it myself, but I can't seem to do anything or progress in fixing it. Again, It crashes my entire game, and I have gotten penalized for it. It only happens in online matches in Blind Pick and Draft for Summoner's Rift, although I have not tried Ranked, and most likely won't, as I have gotten penalized enough already for it. It started when I, or Windows forcefully installed an update for my PC, and I even rolled back the update, but nothing. Please help me, as I just want to play League of Legends while Riven is on rotation.