game stops responding, get kicked, unable to reconnect [crash]

About 2 out of every 3 games I play (usually happens in 5v5,but just happened in ARAM), I get randomnly kicked, game stops responding, says trying to reconnect, never reconnects, i have to use task manager (windows 7) to close the client. Says "game has crashed, click to reconnect". i click, it starts to pull up loading screen then says "unable to connect, check your firewall" no matter how many times i try to reconnect. Sometimes if i close client completely and re-log in it will load in to game, other times it just has the same unable to connect message. No idea what is causing this, I have uninstalled and reinstalled league twice and it still happens. Very frustrating, and leaverbuster keeps punishing me for this when I have no control over it.