Toshiba Satellite L50-A-1EH laptop screen keeps black, what to do?

Hello,

I have a Toshiba Satellite L50-A-1EH laptop. My laptop starts but the screen keeps black. The light of my Caps-Lock and Num-Lock doesn't work but normally it works. I think it doesn't work because my laptop has a black screen. I tried the method with unplugging the battery and holding the power button for 30 seconds and the method worked the first 2 time but now the method doesn't work. I also tried an external monitor but that didn't work. Can someone help me please?

Sorry for my bad English.