The laptop turns on fine, but the screen is dark.
Multiple things can cause the screen to work incorrectly, check below for each possible senario and the actions you need to take to fix the problem.
The problem may be that the brightness setting is too low. Press "F10" on the keyboard repeatedly to increase the brightness setting. Press "F9" to decrease the brightness.
Shine a light onto the screen. If you can see the background and text after shining a light on the screen, the back-light is broken and the screen must be replaced.
If no text is displayed after shining a light on the screen, it is possible that the screen is broken and must be replaced.