Computers · Repair guide

How to fix a computer that turns on but shows no display

9 fixes, easiest first5 min readUpdated November 2026

Quick fix

Check that the monitor is on and set to the input the cable is plugged into, then reseat or swap the cable. On a desktop with a graphics card, plug the monitor into the card's ports, not the ones on the motherboard; if Windows is running, press Windows + Ctrl + Shift + B to reset the graphics driver.

What it means

If the fans spin and lights come on but the screen stays black or the monitor shows "No signal", the PC is getting power but no picture is reaching the screen. The cause is often simple, such as the wrong monitor input, a loose cable or the wrong port, but it can also be a graphics driver, a stuck display mode or a hardware fault.

Common causes

  • The monitor is set to the wrong input or is not powered on
  • A loose or faulty HDMI, DisplayPort or VGA cable
  • The cable is plugged into the motherboard instead of the graphics card
  • Windows is sending the picture to another screen or projection mode
  • A frozen or broken graphics driver, often after an update
  • Memory (RAM) or another part not seated or failing
  • A faulty monitor, laptop screen or graphics card

How to fix it

Work down the list. Each fix is safe to try before moving on to the next.

01Check the monitor power and inputEasy

  1. Make sure the monitor is plugged in and switched on; its power light should be lit.
  2. Use the monitor's buttons to open its menu and choose the input that matches your cable, such as HDMI 1, HDMI 2 or DisplayPort.
  3. If the monitor shows its own menu or a "No signal" message, the monitor works and the problem is the cable, the port or the PC.
  4. On a laptop, turn the screen brightness up with the brightness keys.

Why it helps: A monitor set to the wrong input looks exactly like a PC with no display.

02Reseat or swap the video cable and portEasy

  1. Unplug the video cable at both ends and push it back in firmly.
  2. Try a different cable, and a different port on the PC and on the monitor.
  3. On a desktop with a separate graphics card, plug the monitor into the ports on the graphics card, usually lower down on the back, not the ones near the USB ports.
  4. Remove adapters, docks and splitters for now and connect the monitor directly.

Why it helps: Loose cables and the wrong port are the most common reasons for a "No signal" screen.

03Reset the graphics driver and display modeEasy

  1. If Windows may be running behind the black screen, press Windows + Ctrl + Shift + B together. You should hear a beep or see the screen flicker.
  2. Press Windows + P, then P again and Enter to switch to the next display mode. Repeat a few times, waiting a moment between tries.
  3. If you can see a mouse pointer, press Ctrl + Shift + Esc to open Task Manager, right-click Windows Explorer and choose Restart.

Why it helps: These shortcuts wake a frozen graphics driver or move the picture back to the screen you are using.

04Force a restart with extras unpluggedEasy

  1. Unplug USB drives, docks, extra monitors and other devices you do not need.
  2. Hold the power button for about 20 seconds until the PC turns off.
  3. Wait a few seconds, then press the power button once to turn it back on.
  4. Watch for the PC maker's logo; if it appears and then goes black, the problem is likely in Windows or the graphics driver.

Why it helps: A forced restart clears a stuck startup, and unplugging extras removes devices that can block it.

05Try a different screenEasy

  1. Desktop: connect the PC to another monitor or a TV with a known good cable.
  2. Laptop: connect an external monitor or TV to the laptop's video port.
  3. If the other screen works, the original monitor, laptop screen or its cable is the likely problem.
  4. If no screen shows anything, the problem is inside the PC.

Why it helps: This quickly separates a bad screen from a PC that is not sending a picture.

06Run your PC maker's display or hardware testMedium

  1. If you have a Dell laptop: shut it down, unplug extra devices and connect the charger. Hold the D key, press the power button, and keep holding D until colored screens appear. If the colors show cleanly, the screen itself works. Press Esc to stop.
  2. If you have a Dell desktop or laptop and can see the Dell logo: press F12 repeatedly at the logo and choose Diagnostics to test the hardware. Write down any error and validation codes.
  3. If you have an HP and can see anything on screen: turn the PC off, turn it on and press Esc about once a second until a menu appears, then press F2 to open HP PC Hardware Diagnostics UEFI. Select System Tests, then Fast Test, and write down any 24-digit failure ID.
  4. If you have a Lenovo ThinkPad: turn it on and press F10 right away to open the UEFI Diagnostics tool. For other Lenovo models, check Lenovo's support site for your model.
  5. With no picture at all, listen for beeps or watch for a blinking power or caps lock light, and look up the pattern in your PC's user guide. For other brands, check your PC maker's support site.

Why it helps: The maker's built-in tests can confirm whether the screen, memory or graphics hardware has failed.

07Reseat the memory (desktops only)AdvancedHands-on

  1. Warning: only do this if you are comfortable opening the side panel, and if the PC is out of warranty or your maker allows it. Shut down, switch off and unplug the power cable first.
  2. Press the power button once with the PC unplugged to drain leftover power, and touch a bare metal part of the case to discharge static.
  3. Open the side panel, press down the clips at the ends of each memory stick, lift it out, and press it back in firmly until the clips click.
  4. Close the case, plug the power back in and turn it on.
  5. Do not remove any other parts; if there is still no display, contact a repair shop.

Why it helps: A memory stick that has worked loose stops the PC starting properly, often with fans running and no picture.

08If it started after an update: roll back the display driver in Safe ModeAdvanced

  1. If the logo shows but Windows goes black, hold the power button for 10 seconds to turn the PC off. Turn it on and repeat this 2 or 3 times until the recovery screen appears.
  2. Choose Troubleshoot > Advanced options > Startup Settings > Restart, then press F5 for Safe Mode with Networking.
  3. In Safe Mode, open Device Manager, expand Display adapters, right-click your graphics adapter and choose Properties.
  4. On the Driver tab, select Roll Back Driver if it is available. If not, choose Update driver or download the latest driver from your PC maker or graphics card maker.
  5. Restart the PC normally.

Why it helps: A new graphics driver that does not work with your hardware can leave the screen black after Windows starts.

09Use System RestoreAdvanced

  1. Warning: System Restore removes apps, drivers and updates installed after the restore point. Your personal files are not changed, but back them up if you can.
  2. From the recovery screen, choose Troubleshoot > Advanced options > System Restore.
  3. Pick a restore point from before the black screen started and follow the prompts.
  4. Let the PC restart and finish the restore before you turn it off.

Why it helps: Restoring to an earlier point undoes a recent change that stopped the display from working.

Check it's fixed

  • The PC maker's logo and the Windows sign-in screen appear on the monitor.
  • The monitor no longer shows "No signal" after a restart.
  • The picture stays on after the PC wakes from sleep.

When to get help

If no screen shows anything, the maker's tests report a failure, or you hear beep codes or see blinking light codes, contact your PC maker or a repair shop. Do the same if the PC smells of burning or turns off by itself.

Questions

Why does my monitor say No signal when my computer is on?

The monitor is not getting a picture from the PC. The usual reasons are the wrong input, a loose cable, or plugging into the motherboard instead of the graphics card.

Why does my screen go black after a Windows update?

An update may have installed a graphics driver that does not suit your PC. Try Windows + Ctrl + Shift + B, then roll back the display driver in Safe Mode.

My laptop turns on but the screen is black. Is the screen broken?

Not always. Connect an external monitor: if it shows a picture, the laptop screen or its connection is likely at fault. Dell laptops also have a built-in screen test you start by holding D and pressing power.

Can bad RAM cause no display?

Yes. Memory that is loose or failing can stop the PC from starting, often with fans running and a black screen, sometimes with beeps or blinking lights.

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