Hold the D key  through powerup.  That should initiate a screen self test.  Does it?

What model XPS is it?  9330, 9350, 7590, etc.?

Well I will suggest you to try the following:

1.Power Reset
2.Check for Backlight
3.External Display: Connect to an external monitor
4. Try the Keyboard Shortcut Press Fn + F8 (or Fn + Display icon) to toggle between display modes.
5.BIOS Access
6.Boot into Safe Mode
7.Check Display Cable
8.Check Display Cable

@ejn63​ how can i see the model xps

@ejn63​ dell precision 3550 my laptop model number i do the ram cleaning and and i also access the bios but it's not access the bios

Retrace your steps, including unplugging the system and removing the base cover.  Disconnect the battery from the mainboard and hold the power button for 30 sec.   Remove and reinstall the memory module(s) and storage drive.

Then reassemble and try again.