Just about 2 hour ago I put my mac on standby because I had to do some homework, but after I finished my work and opened up my computer, the screen was black. I then resetted the computer by holding the power button down but still nothing. The computer makes all the sounds like it normally does, it does the chime aswell. However, when I close the computer up the front light isn't pulsating, its just glowing. While my computer's screen is black I can adjust the sound (it makes the noises) and I can adjust the backlit keyboard brightness, but it doesnt respond to trying to light up the desktop. I've tried to shine a light to the desktop but can't see anything. I've tried looking at some similar posts, tried to reset it up by holding cmd+opt+p+r.. nothing works. I can't understand this... it was working just fine only hours ago Suggestions are very much appreciated, thanks in advance. EDIT: after leaving it for 10 minutes, the front light started pulsating as normal again, but when I open it up, black screen still.