I had been using my MBP all morning with no problems. I shut the screen and let it go into sleep mode for about an hour before I went back to get on it. At first I thought it just wasn't waking up from sleep mode, because the screen just stayed black but the fans booted up and I could hear it running. So, I shut the lid again, opened, and nothing. Tried rebooting. The screen stays black the entire time, and I hear the faint sound of the start up sound. When I close the screen, the light at the front doesn't do the "breathing" that it does when in sleep mode. It just stays lit. Does this sound like a display problem, or some other issue? Any ideas/suggestions?