This would also require repair, and may not be viable on cost. In this case, because the backlight will be on but the LCD screen turned to black, in a dark room you will normally be able to see a slight blue-grey glow from the screen.
I held down the power button to force a shutdown, then powered up again, but the screen remained black still even. I closed the lid, it went into sleep mode as expected, and when I opened the lid the screen remained black. Dell desktops, laptops, and tablets built since 2009 and running Windows can be. Scottv, I have the EXACT same problem with my HP Pavilion dv2000 laptop. If the torch test doesn't reveal any Windows desktop image, the fault is probably in the video chip that drives the screen. Again select Update Driver Software but this time on the next screen. Any of these requires getting service access into the laptop, and unless you're handy, probably best dealt with by a repair shop.
If you see this, the probable causes are a faulty backlight, a faulty inverter or faulty connection, e.g. If the screen is actually generating an image but the backlight is not on to light it up, the light spill shining back out of the screen will show the Windows desktop dully around the torch.
A quick way to check is with the room dimly lit, shine a torch very close to the surface of the screen while the laptop is on. Otherwise, the commonest cause of that symptom is the backlight not lighting. Firstly, make sure there isn't a button or key combination been activated to turn off the internal screen and use external only.
