After using my macbook, putting it to sleep, and then trying to start it back up again after not using it for an hour or so, it started doing weird things. First, when I started it up after being is sleep mode, nothing would open after clicking. It showed that it was loading and then never stopped. I tried to restart it, but it wouldn't restart, so I held down the power button until it shut down. After waiting a few seconds, I tried to reboot it...and this is were I got really confused. The screen went white (or light blue, idk) and what looked like a picture of a folder with a white question mark on it started flashing on the screen. I waited to see if I could click on anything or if any options would come up, but nothing happened. I pressed the power button and the screen went black almost immediately. I waited a couple of seconds and tried to start it up again and the same thing happened. I then shut it off again and went to the other computer to see if I could find out why it was doing that. While waiting for things to load, I decided to try to start up my macbook one more time..and it turned on and started up perfectly fine! Does anyone know what might have caused that to happen? I'm really confused and don't want it to become an even bigger problem in the future.