Your screen is dark, but your computer might still be running

A blank screen does not always mean your computer is off. The machine itself could be running normally while the display stays dark because of a loose cable, a monitor that is not powered on, or a graphics setting that has changed. Before you assume the worst, work through the physical connections first—they solve most cases in under five minutes.

The most common culprit is a cable that has come loose or a monitor that is switched off. The second most common is a computer that has gone into sleep mode and needs a keystroke or mouse movement to wake. After those, you are looking at graphics driver issues, BIOS settings, or hardware failure—but you will not reach those until you have ruled out the straightforward stuff.

Key Takeaways

  • Check that both the monitor power cable and the video cable connecting the monitor to the computer are fully seated in their ports.
  • Make sure the monitor itself is powered on—look for a power light on the front or back of the display.
  • Press a key or move the mouse to wake the computer from sleep mode, which can look identical to a powered-off state.
  • If the computer is making noise and lights are on but the screen stays dark, the issue is likely graphics-related rather than a power failure.
  • Reseating the graphics card or updating the graphics driver often restores a display that was working before.

Check the monitor power and cables first

Start by looking at the back of your monitor. You should see a power cable plugged into an outlet and a video cable (usually HDMI, DisplayPort, or VGA) plugged into both the monitor and the computer. Unplug both cables, wait ten seconds, and plug them back in firmly. A cable that looks connected may actually be loose enough to break the signal.

Next, look for a power button or light on the monitor itself. Many monitors have a small LED that glows when they are on. If you do not see a light, press the power button on the monitor—it is usually on the front bezel or the bottom edge. If the monitor has no power light and does not respond to the button, try a different power outlet to rule out a dead circuit.

If you have a laptop, check whether the screen brightness has been turned all the way down. Look for brightness keys on your keyboard—usually marked with a sun symbol—and press the one that increases brightness several times. Some laptops also have a keyboard shortcut like Fn + brightness key that you may have hit accidentally.

Wake the computer from sleep mode

If the monitor is on and the cables are tight but the screen is still black, your computer may be in sleep mode. Press any key on the keyboard or move the mouse. If the screen lights up, the computer was asleep the whole time. This is especially common on laptops and on desktop computers that have been idle for a while.

If pressing a key does nothing, hold down the power button on the computer for three seconds. This should wake it from sleep. If the computer does not respond at all—no lights, no fan noise, nothing—then the power supply itself may be the problem, and you should check the power cable and outlet the same way you checked the monitor.

Listen and look for signs the computer is actually running

Before you go further, determine whether the computer is powered on at all. Listen for fan noise coming from the case. Look for lights inside the case or on the front panel. If you see lights and hear fans, the computer is running—the problem is the display, not the power. If you see nothing and hear nothing, the computer is off or the power supply has failed.

If the computer is running but the screen is dark, try connecting the monitor to a different video port on the back of the computer. Many computers have multiple ports—HDMI, DisplayPort, and VGA are common. Unplug the video cable from the current port and plug it into another one. This rules out a single dead port.

On a desktop with a graphics card, you may also have video ports on the motherboard itself (usually near the power connectors at the back). Try plugging the monitor into those instead. If the screen comes on, your graphics card may have failed or come loose.

Reseat the graphics card if you have a desktop

If your desktop computer is running but the monitor stays dark, and you have a dedicated graphics card (a separate card plugged into the motherboard, not just built-in graphics), the card may have come loose. Power off the computer completely, wait ten seconds, then open the side panel of the case.

Locate the graphics card—it is a long rectangular board plugged into a horizontal slot on the motherboard, usually near the back of the case. Press down on the small clip or lever at the end of the slot to release the card, then pull the card straight out. Wait a few seconds, then push it back in firmly until you hear or feel it click into place. Close the case, power on the computer, and check the monitor.

If reseating the card does not work, try moving it to a different slot if your motherboard has more than one. Some slots are faster than others, but any slot should produce a display signal.

Update or reinstall the graphics driver

If the computer is running, the monitor is on, the cables are tight, and you have reseated the graphics card but the screen is still dark, a corrupted or outdated graphics driver may be the cause. This is especially common after a Windows update or if you recently installed new hardware.

Boot the computer into Safe Mode, where Windows loads only essential drivers. Restart the computer and hold down F8 or Shift as it boots (the timing varies by Windows version—you may need to try a few times). Select Safe Mode from the menu. If the screen comes on in Safe Mode, the graphics driver is the problem.

Once you are in Safe Mode, go to Device Manager (right-click the Start button and select Device Manager). Find Display Adapters, right-click your graphics card, and select Uninstall Device. Restart the computer normally. Windows will reinstall a basic driver, which may restore the display. If it does, read the latest driver from your graphics card manufacturer's website (NVIDIA, AMD, or Intel) and install it properly.

Check BIOS settings if nothing else works

If the computer runs, the monitor is on, cables are seated, and the driver is updated but the screen is still dark, the BIOS may have been set to disable the display output. This is rare but happens sometimes after a power surge or a failed update.

Restart the computer and enter the BIOS setup. The key to press varies by manufacturer—common ones are Delete, F2, F10, or F12. You will see a message on the screen during startup telling you which key to press. Once in the BIOS, look for a setting related to graphics, display, or integrated graphics. Make sure it is set to Enabled or Auto, not Disabled. Save and exit.

If you cannot find the setting or the screen is too dark to read the BIOS menu, try resetting the BIOS to factory defaults. There is usually a Reset option in the BIOS menu, or you can remove the CMOS battery from the motherboard for thirty seconds and reinstall it. This erases all BIOS changes and restores defaults.

When to replace the monitor or seek repair

If you have worked through all the steps above and the screen is still dark, the monitor itself may have failed, or the computer's graphics hardware may be damaged. A monitor that will not power on, shows no light, and does not respond to the power button is likely dead and will need replacement.

A computer that runs but produces no display signal after driver updates, cable checks, and BIOS resets may have a failed graphics card or motherboard. At this point, a repair technician can test the hardware with diagnostic tools and tell you whether the card or board can be replaced or if the whole machine needs replacement.

Frequently Asked Questions

Why is my screen black but my computer is making noise?

The computer is running but the display is not receiving a signal. Check that the video cable is plugged into both the monitor and the computer, and that the monitor is powered on. If those are fine, try a different video port on the back of the computer, or reseat the graphics card if you have one.

My monitor has power but still shows nothing. What do I do?

The monitor itself may be working but not receiving a signal from the computer. Unplug the video cable from both ends, wait five seconds, and plug it back in firmly. Try a different video port on the computer. If the monitor still shows nothing, the monitor may have failed internally and will need replacement.

Can a Windows update cause the screen to go dark?

Yes. A Windows update can corrupt the graphics driver or change BIOS settings. Boot into Safe Mode to see if the screen comes on with basic drivers. If it does, uninstall the graphics driver and let Windows reinstall it, then read the latest driver from the manufacturer's website.

What if I hear beeping sounds when I turn on the computer?

Beep codes tell you what hardware is failing. One long beep followed by two short beeps usually means a graphics card problem. One long beep and one short beep usually means a memory problem. Consult your motherboard manual for the exact meaning, or reseat the graphics card and RAM modules to see if that fixes it.

Is it safe to open my computer case and reseat the graphics card?

Yes, as long as you power off the computer completely and wait ten seconds before opening the case. Touch a metal part of the case to discharge static electricity before touching any components. Reseating a card is a straightforward, low-risk step that fixes many display problems.