@ralphperez Start off with the easy things. Disconnect the power from the computer by unplugging the power cord from your computer. Disconnect all external devices from the computer. Remove the battery Now hold the power button depressed for about 30sec-1min. Reapply the AC power adapter and see if your computer's display now shows any sign of life.
Next you want to connect an external monitor. See what that displays. If that continue to show nothing, then the issue can be related to your video circuitry of your computer. If an external monitor does show the desktop etc. you have issues with your computer's display. Could be the LCD or could be a bad cable, display connector issues etc.
To work on your computer, use this [document|35365]. Let us know what you find out so we can continue to assist you with this repair.