Why is my laptop screen not booting?

The laptop wont ever turn on and when i hit the power button, the keyboard backlit turns on, and i hear a beep and fan running. The screen is pitch black and shows no response no matter how much the time passes. Also the laptop over heats .e.g when i keep it on for over 15 minutes its like the heat emitting from the machine would melt the plastic under-body. I sincerely need your help in trying to figure out what the problem is and how i can make it better. I do have an external monitor.