Are you able to see the Windows Welcome screen? I would suggest you to follow the below mentioned steps which could help us to isolate the issue:
•Remove the battery and charger/ac adapter/power cord from your Dell notebook, press and hold the power button for 20 seconds to discharge any residual current inside the laptop. This clears RAM and resets the hardware.
•Try increasing the computer brightness.
•Connect to an external monitor (if available), when the external monitor does work it may be an issue with the Operating System or it could even be the LCD. In case it’s not LCD, verify that the video drivers are the latest.
•Run LCD or Hardware diagnostics.
Please reply if you have any further questions.
Thanks & Regards