Client Crashes randomly(This has been happening for weeks now)

Client Crashes randomly(This has been happening for weeks now) and because of this I get a penalty for leaving a champ select that i couldn't even help. The bug splat appears and after 4-5 secs the client crashes. This happens randomly even if the client is idle or if Im in a champ select. Something the client crashes while I am in game but the game doesnt crash, I can play the game but the client wont be available to report/honor people(unless i go alt+tab and restart the client and login again)