Opening Client Crashes Entire Computer [CRASH]

This is a problem that just occurred for me. I log onto my computer and decide to play some league, pretty normal. After launching and signing in, i open league and the client is up for about 4 seconds until it crashes my entire computer so i have to restart it. I repeated this many times over. I've tried changing compatibility mode from default to the OS i am on (Windows 8.1) and still nothing. It might be irrelevant, but the first time it happened i was listening to a YouTube video in the background and the audio kept playing for about 10 seconds after the mouse and keyboard became unresponsive. I would like support ASAP because i cant play at all until this is fixed. (Also my computer just updated last time i shut it down if that means anything.)