WTF??

So, I open League and everything, just like normal. I press "Launch," log in, and then, I to the main page where I can get in queue, or go to the shop or whatever. However, the second I log in, the game freezes. It also freezes my entire computer. I can't even press ctrl+alt+delete. I have to press on my computer's power button so my computer works again. My friends have also encountered this problem. What is it??