So.... problem not resolved yet, i got in contact with apple, and i was told to send my mac by mail to another city (yes, apple dont have a single authorized service here ), so i tought... when i plug my mac on a external monitor, it works normally, is this because the mac turns on the nvidia grapichs ?... if yes, manually turning it on alll the time should be an workaround?
As was pointed out to you previously, there appears to be a defect with your (integrated) GPU. There's nothing for you to do but wait until Apple repairs it by changing the logic board.