Bug

I'm fairly sure it's a bug, but when I play Aram, usually more towards the end game, when there is a lot going on, abilities being thrown around and stuff, my entire pc freezes, this causes me to leave games and I think I'm going to get leaver busted soon, I love Aram but it always freezes my toaster, I can't Tab out, open task manager or anything, all I can do when this happens is press and hold my power button (_) anyone have any insight or suggestions?