Game Freeze After Loading Screen

Hi guys,

There's a bug with this game that whenever I start a game after the loading lobby screen my computer freezes. Nothing seems to work including all keys and mouse. The only thing I can do is force shutdown. i have to shutdown come back on and reconnect. It only happens the first time when I open league. I think it happens with both PvP and Bot games. Is there a way that I can fix it? I hate to keep on shutting down my computer the improper way. Plz help! Thanks.