Client freezes and crashes all the time, pls help ! :(

it always freezes in lobby, champ select, basically anywhere. I have to wait like 5 mins every time just so it can return to normal ..... really sucks when i go into ranked and it freezes and i get a 5 min ban.... any solution please!!!

Its getting a lot worse lately, it used to be for like only 2-5 mins, but now i have to quit and relog just to fix the problem .... :(