Unable to join matches since Friday.

So on Friday I logged onto LoL and there was a mini update. It took less than a minute for it to load up and stuff on my LoL client (this wasn't 7.1). Ever since then, whenever I enter champion select, my computer slows down drastically, I'm unable to google stuff because it's moving so slowly, and the loading screen never appears for me. I can't control alt delete to get to task manager and shut it down. The only way I can turn off my computer is by using the power button on the desktop.

I figure it has something to do with that mini update because my computer is working fine except when I load up a game of LoL. Any suggestions on what to do?