Freezing Game

When I try to play a game sometimes my client will randomly freeze. It won't let me Alt Tab out of my games or continue to walk. I can't move my character and everything is frozen. To fix this issue I always have to restart my computer, shut it down, or log out. I assumed it was an issue with my computer but League of Legends is the only application that it does it with. Can you please help me with any type of solution please.