Once a game, almost every game, league just freezes and there is nothing I can do.

The window just gets frozen. It does not let me alt tab. I cant even open task manager. The screen just stays open, completely unresponsive. It has only happened once a game, but it has happened almost every single game for weeks. I thought it was a problem with my computer, but i updated my graphics drivers and the problem is still there. This does not happen with any other game or application.