Game Crashes before victory/defeat screen A LOT

Okay, so, I have no idea why/how this is happening, but on about two of every three games I play league will crash on the victory or defeat screen right before the nexus explodes. It used to be that I could just go into the task manager and close league, but now on 2 of my last 3 games league has completely frozen my entire laptop so that I had to force shut down my computer and reboot it.

Is there ANYTHING AT ALL I can do to fix this, because it is getting insanely frustrating and pissing me the hell off

Jascha