Monitor no signal: how to fix it

Applies to: desktop PCs and laptops with an external monitor on Windows 11 and Windows 10. Most checks also apply to TVs used as monitors.

First: is it the monitor or the PC?

If the monitor shows its own No signal, No input or Check cable message, or its on-screen menu opens, the monitor itself works. It just isn’t getting a video signal. That narrows the problem to the input setting, the cable, the port, or the PC’s graphics.

To confirm, connect the monitor to another device, such as a laptop or games console. If it shows a picture there, focus on the PC. If it still says no signal with a known-good device and cable, the monitor’s port or the monitor itself is at fault.

Fix 1: Check power and the input source

1. Make sure the PC is actually on: listen for fans and look for power or keyboard lights.
2. Press the monitor’s Input, Source or menu button and select the port your cable is in, for example HDMI 1 or DisplayPort. Some monitors don’t switch automatically.
3. Turn the monitor off at its power button, unplug it from the wall for about 30 seconds, then plug it back in and turn it on.

Fix 2: Reseat or swap the cable and port

• Use the graphics card ports: on a desktop with a separate graphics card, the video outputs on the motherboard (near the USB ports) are usually disabled. Plug the monitor into the ports on the graphics card, lower down on the back of the case.
• Reseat the cable: unplug both ends and push them back in firmly. DisplayPort plugs often have a latch, so press it to remove them.
• Try another cable and port: damaged or low-quality cables are a common cause, especially at high resolutions and refresh rates. Try a different HDMI or DisplayPort port on both the PC and the monitor.
• Remove adapters and docks: connect the monitor directly to test. A USB-C port only carries video if it supports DisplayPort Alt Mode or Thunderbolt, so check your laptop’s specs.

Fix 3: Wake the PC and reset the graphics driver

If the screen went dark while the PC was running, Windows may have lost track of the display.

1. Move the mouse or press a key in case the PC is asleep.
2. Press Win + Ctrl + Shift + B. The screen may flash and you’ll hear a beep as Windows restarts the graphics driver.
3. Press Win + P and choose Extend or Duplicate. With a blank screen, press Win + P, then the down arrow key and Enter a couple of times to cycle through modes.
4. If nothing changes, restart the PC. A full restart also clears problems that survive a normal shutdown with Fast Startup.

Fix 4: Undo a resolution or refresh rate the monitor can’t show

If the signal disappeared right after you changed the resolution or refresh rate, the monitor may not support the new setting. Windows usually reverts after 15 seconds if you don’t confirm, but if it didn’t:

1. Restart into the recovery menu: hold Shift while selecting Restart, or, if you can’t see anything, turn the PC off during startup two or three times in a row until the recovery screen appears.
2. Go to Troubleshoot > Advanced options > Startup Settings, select Restart, then press 3 for Enable low-resolution video.
3. Once Windows starts, open Settings > System > Display and set a resolution the monitor supports. Check the refresh rate under Advanced display.

Fix 5: Roll back or reinstall the display driver

1. Right-click Start and choose Device Manager. Expand Display adapters.
2. If the problem started after a driver update, right-click the adapter, choose Properties > Driver > Roll Back Driver.
3. Otherwise choose Uninstall device, tick Attempt to remove the driver for this device, and restart. Then install the latest driver from NVIDIA, AMD, Intel or your PC maker.

If you can’t see anything at all, do this from Safe Mode (option 4 in Startup Settings) using another monitor or the laptop’s own screen.

No signal from the moment you power on

If the monitor says no signal before the maker’s logo or BIOS screen ever appears, Windows isn’t involved yet. Check these hardware causes:

• Recently added RAM, graphics card or other parts: turn the PC off at the wall, then reseat the memory and graphics card. Make sure the graphics card’s power cables are connected.
• Beeps or diagnostic lights: many motherboards show a coloured LED or beep pattern for CPU, memory or VGA faults. Look up the code in your motherboard manual.
• Integrated graphics after removing a card: some BIOS settings route video only to the graphics card. Reset the BIOS to defaults (load optimised defaults, or clear CMOS as your manual describes).

If you see the logo but then a black screen, see Windows black screen fixes. If the PC crashes with a blue screen after the picture returns, see WHEA uncorrectable error.

Related guides

• Windows black screen: how to fix it
• How to disable Fast Startup in Windows 11 and 10
• WHEA uncorrectable error: how to fix it
• Mouse cursor disappears in Windows: how to fix it

Official sources: for more detail, see Microsoft’s own documentation:

• Microsoft Support: Troubleshoot external monitor connections in Windows

Frequently asked questions

Why does my monitor say no signal when the PC is on?

The monitor isn’t receiving video. The usual causes are the wrong input source, a loose or faulty cable, the cable plugged into the motherboard instead of the graphics card, or a graphics driver problem.

Can a bad HDMI cable cause no signal?

Yes. A damaged cable, or one that can’t handle the resolution and refresh rate you’re using, often causes no signal or a picture that drops out. Swapping the cable is a quick test.

How do I fix no signal after changing the refresh rate?

Wait 15 seconds for Windows to revert. If it doesn’t, start Windows with Enable low-resolution video from Startup Settings and pick a supported setting.

Why does my second monitor say no signal?

Press Win + P and choose Extend, then check Settings > System > Display and select Detect. Also make sure your graphics adapter supports more than one monitor; a simple HDMI splitter can only duplicate, not extend.