Black screen, but the computer is on? How to narrow it down

The computer is clearly on. The fans spin, the power light glows, maybe the keyboard lights up or you hear the Windows chime. And the screen stays black. This is a different, usually smaller, problem than a computer that will not turn on, and two tests you can do in five minutes will tell you which kind of problem it is.

First, confirm it is really on

• Press Caps Lock. If its light toggles, the computer is awake and running.
• Listen for the startup sound, or press the volume keys and listen for the click.
• If nothing responds at all, you may have a no-power problem instead. Our laptop won’t turn on guide covers that one.
• Hold the power button for 30 seconds, let go, then start it normally. Stuck display states clear this way more often than you would think.

Laptop: the flashlight test

Shine a phone flashlight at the screen at an angle and look closely. If you can faintly make out the desktop, the login screen, or a cursor, the screen is working and its backlight is not. That is a backlight or screen fault, or the cable that feeds it, and the laptop itself is fine. If there is nothing at all, keep going.

Laptop: the external monitor test

Plug the laptop into a TV or monitor with an HDMI or USB-C cable, give it a moment, and press the Windows key and P together, then Enter, a couple of times to cycle display modes. On a Mac, an external display usually just appears.

• Picture on the external screen: the laptop is working, and the fault is the built-in screen, its cable, or the connector on the board. Your files are fine, and the laptop is usable on the big screen until it is fixed. This is the common outcome.
• No picture anywhere: the problem is before the screen. Memory that has come loose, a graphics fault on the board, or Windows not getting far enough to draw anything. This is where the bench earns its keep.
• A faint image with the flashlight plus a good picture outside both point the same way: the built-in screen or its backlight.

Desktop: check the monitor before the computer

• Look for a power light on the monitor and a message such as “No signal” or “Check cable”. A monitor that says no signal is working; the computer is not sending it anything. A monitor that is completely dark with no light may itself be the problem. Try its power cable in another outlet.
• Press the monitor’s input or source button. It is very common for a monitor to be sitting on HDMI 2 while the computer is on HDMI 1.
• Unplug and firmly reseat the video cable at both ends, or try a different cable.
• If the computer has a graphics card, make sure the cable is in the card’s port, not the one on the motherboard above it. If it is in the card and gives nothing, try the motherboard port as a test.
• Borrow another monitor or a TV. Picture there means the monitor is the fault, and our monitor repair page explains when a monitor is worth fixing.

What it usually turns out to be

• A cable worn through inside the hinge. Laptops that flicker when the lid moves, or only show a picture at certain angles, are telling you this.
• A failed backlight or screen. On a laptop the whole panel is replaced; it is ordered for the exact model, and it is a routine job.
• A cracked panel with no visible crack on the outside, after a drop or a bag squeezed too tight.
• Memory that has come unseated, especially after a bump or a move. Often a five-minute fix.
• Windows itself stuck on a black screen with a moving cursor. That is software, not the screen, and it is fixable without a part.
• A graphics fault on the board. The least common and the one where we tell you honestly whether the fix is worth it.

What we do with it

For the flat $60 we run the same tests properly on the bench, with a known-good screen and monitor, and tell you which it is. Screens are ordered for your exact model and come with a 30-day warranty on parts and labor. A loose cable or memory stick is often fixed on the spot. If it is the board, you hear the real cost before deciding, and if that is not worth it, your files come off the drive either way. The $60 comes off the repair. See our laptop screen repair page for the screen side of this, and computer repair for everything else.

When to bring it in

When the two tests point at the built-in screen, when nothing shows anywhere, or when the monitor and cable swaps did not help on a desktop. Bring the charger, and bring the monitor too if it is the suspect. Walk in Monday through Thursday, 9:00 to 5:30, or Friday by appointment, at 746 S Arnold St Suite 3, the black door with our logo on it, straight ahead when you pull in, up the steps. Or book a drop-off online. Every price we charge is on our prices page.