Computer Crashes after League Launches Game

Only when I play ranked, or (now Clash), when my game is launched, my whole computer freezes and I have to restart my whole computer to get it to work. This only happens in Ranked and Clash which is really weird. I will play 20 games of 5v5 Normal and I will not crash once but if I queue up solo/duo ranked, it occasionally happens. I think it might be because I have a gaming laptop and I use an HDMI 2.0 to port my display to my main monitor. Is there anything I should do to prevent it?