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.