Monitor says 'no signal'? Fix a blank screen

1. Confirm the monitor is on the correct input. Most monitors have a physical or on-screen button to cycle between HDMI 1, HDMI 2, DisplayPort and so on. Press the input/source button on the monitor itself.
2. Check the cable is fully seated at both ends. HDMI and DisplayPort connectors can look plugged in while sitting loose enough to drop the signal.
3. Try a different cable. Cables fail more often than people expect, especially cheap or well-worn HDMI leads.
4. Wake the computer. If it's asleep or hibernating, wiggle the mouse or press a key; a monitor showing no signal while the PC is sleeping is completely normal.
5. Power-cycle both the monitor and the computer. Turn both off, unplug the monitor's power cable for 30 seconds, then reconnect everything and turn the PC on first, then the monitor.

The fastest way to isolate the fault is to swap one variable at a time.

1. Try the same cable and monitor on a different port on the computer, for example a second HDMI or DisplayPort output if your GPU has one.
2. Try a different cable type entirely if your monitor and GPU support more than one, for example DisplayPort instead of HDMI.
3. Try your monitor with a different computer or laptop, if you have access to one, to see whether the monitor itself displays anything at all.
4. Try a different monitor or TV with your original computer and cable to confirm the computer is actually outputting a signal.

If a monitor works with one device but not another over the same cable, the fault is almost always the graphics output on the device that fails, not the monitor or cable.

If your PC has a dedicated graphics card, the motherboard's built-in video output is usually disabled once a GPU is installed. Plugging a monitor into the motherboard port instead of the graphics card port produces exactly this no-signal symptom.

• Look at the back of the case: the motherboard ports are usually higher up near the USB ports, while a dedicated GPU sits lower, often in its own slot with its own ports.
• Make sure the cable goes into the card that's actually installed and seated properly in its slot.

This pattern usually points to a resolution or refresh rate mismatch rather than a connection problem. The computer boots and sends a basic signal (which the monitor can display), then switches to a resolution or refresh rate the monitor doesn't support once the operating system loads.

• Boot into Safe Mode (Windows) or Safe Boot (Mac), which forces a basic, universally compatible resolution, then adjust your display settings from there.
• On Windows, boot into Safe Mode, go to Settings > System > Display, and lower the resolution and refresh rate to a standard setting like 1920x1080 at 60Hz before restarting normally.
• If you recently updated graphics drivers or Windows, this is a common trigger; rolling back the driver from Device Manager can resolve it.

Once you get a picture, run our Display Test to check for dead pixels, colour accuracy and confirm your resolution is being reported correctly. If you suspect the graphics card rather than the monitor, our GPU Test will identify the chip and confirm it's rendering properly.

• If the monitor shows no signal with every cable, port and device you try, but powers on and shows its own menu correctly, the monitor's input board or main board has likely failed.
• If the monitor doesn't even power on, or the power LED doesn't light, check the power cable and outlet first, then suspect the internal power supply.
• If a laptop's own screen also stays black even though an external monitor works fine through the same GPU, that points to a failed laptop screen, backlight or display cable rather than the graphics card.
• Persistent flickering, lines, or a picture that appears and disappears with slight pressure on the cable connector at the monitor usually indicates a damaged port or internal connector needing professional repair.

A no signal message is the monitor telling you it powered on, checked its inputs and found nothing arriving. That is genuinely useful information, because it proves the display is alive. The fault lies in the chain between the graphics output and the monitor input: the port you used, the cable, the input selected on the monitor, or the computer not producing an output signal at all.

It also rules out a surprising amount. A monitor with a completely dead backlight shows nothing, not a message. So if you can read no signal, the panel, the power supply and the on-screen menu system are all working, and you are looking for a connection or configuration problem rather than a broken display.

Change one thing at a time and retest, otherwise you will fix it without knowing what fixed it and the problem will return.

1. Select the input manually on the monitor rather than trusting automatic detection, which fails often.
2. Reseat both ends of the cable firmly, DisplayPort in particular has a latch that can sit half engaged.
3. Swap the cable for a known good one, cables fail more often than any other component in this chain.
4. Try a different port on the computer and a different input on the monitor.
5. Test the monitor with another source such as a laptop or games console to prove it can display anything.
6. Test the computer with another display to prove it is producing output at all.

After two of these swaps you will know which side owns the problem, which is more than most people establish after an hour of trying random things.

Higher resolutions and refresh rates demand more bandwidth, and a cable that worked perfectly at 1080p can fail entirely at 4K or at 144Hz. The failure often is not gradual, it is a blank screen, which makes it look like a dead port rather than a bandwidth limit.

• Use a certified high speed HDMI cable for 4K at 60Hz and above, and check the version the monitor requires.
• DisplayPort generally carries more bandwidth than HDMI at the same generation and is preferable for high refresh gaming.
• USB-C video requires the port to support DisplayPort alternate mode, not every USB-C port does, even on the same laptop.
• Adapters and long cables add failure points, keep the chain as short and simple as possible while diagnosing.
• If the picture appears at a lower refresh rate but not a higher one, the cable or port bandwidth is your limit.

Laptops add complications that desktops do not have. Many route external video through the integrated graphics rather than the discrete card, some disable external outputs on battery power to save energy, and docking stations introduce their own firmware layer that can fail independently of everything else.

• Connect the display directly to the laptop first, bypassing the dock, to see whether the dock is at fault.
• Plug the laptop into mains power, some models restrict external displays on battery.
• Update the dock firmware, this fixes a genuinely large share of intermittent external display faults.
• Check the lid closed behaviour setting if the display only works with the lid open.
• Use the keyboard shortcut or display settings to cycle projection modes, an extended desktop set to a disconnected display shows nothing.

Once you have a picture, verify the display itself properly rather than assuming everything is fine. A full screen colour and uniformity check reveals dead pixels, backlight bleed and colour banding that a desktop wallpaper hides completely.

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