I encountered the same issue on my Canon eos 1500d the display was off. it turns only when we switch it to Video mode(but was not able to record in video mode) Camera flash automatically pops up tooks photos. Solution : (1) I have removed the Card from camera and formated ( this is not needed by the way) (1) charged the battery to full (2) dont remove the cameras lens cap (3) put the camera to manual mode (4) Take a photo (5) then after 1 or 2 second click on any button ( delete/preview..etc ) this turned my display on and there is no issue till now. if this doesnt works in the first try tey again next day