League Isn't Working at All

I have been playing League nonstop for a couple months or so and I can't get enough. Recently, my computer has been freezing randomly both in game, lobby, or anywhere in launching process (and literally everywhere else) almost like it is being overloaded with commands and has to take a minute or two before I can do anything again. This started a little under a week ago and I'm having a hard time getting my fix in with this game. I'm about to try reinstalling but if that doesn't work, I'm gonna be lost and without a clue of what to do. Please help me figure out how I can satisfy my need to league! FYI, my whole computer freezes with League, but it only happens when I have League up and running.

Update: I tried to play a game and as soon as the loadout screen went to start the game, the actual League client you play on crashed. I can't even run the actual game anymore and I'm very worried that my computer has a virus or something. Please help ASAP.