very weird lol crash.l can bet its the most weirdest lol crash ever

so when i enter a game,i can play until like 5 minutes.then my screen goes crazy.i see minions very bugged and my screen goes black with blue dots in minios position. i go ctrl alt del and then my screen is okay,but it has like white lines every where
i play lots of games but it happens only when playing lol my computer is pretty good too i think its a lol bug please tell me what to do so i can play with my friends