No Display on Monitor (No Signal)? Fix It Step by Step

Seeing “No Signal” on your monitor or getting a completely black screen can be frustrating, especially when the computer itself appears to be running.

The problem can be caused by something simple, such as the wrong input source or a loose HDMI cable. It can also involve the graphics card, display settings, RAM, ports, adapters or other hardware.

This guide walks you through practical checks to help identify the cause of a no-display or no-signal problem and get your monitor working again.

Why Does My Monitor Say “No Signal”?

A monitor displays “No Signal” when it isn’t receiving a usable video signal from the computer or another connected device.

Common causes include:

• Loose or damaged display cables
• Incorrect monitor input selection
• Problems with HDMI, DisplayPort or USB-C connections
• A graphics card issue
• A computer that hasn’t started correctly
• Incorrect display settings
• A faulty monitor port
• A problem with the computer’s video output
• RAM or POST-related hardware problems
• An adapter or docking station problem

The easiest approach is to start with the simple checks before moving on to more advanced troubleshooting.

1. Check the Monitor Power and Indicators

Start with the monitor itself.

Make sure:

• The monitor is switched on.
• The power cable is firmly connected.
• The power outlet is working.
• The monitor’s power indicator is illuminated.
• The brightness hasn’t been reduced completely.
• The monitor isn’t showing a different error message.

If the monitor has no power indicator at all, the problem may be related to the power supply, cable, outlet or monitor rather than the computer’s video output.

Try a different power outlet if one is available.

2. Check the Monitor Input Source

Modern monitors often have multiple video inputs.

For example, your monitor might have:

• HDMI
• DisplayPort
• USB-C
• DVI
• VGA

If your computer is connected through HDMI but the monitor is set to DisplayPort, the monitor may display “No Signal.”

Use the monitor’s buttons or controls to select the input that matches the cable you’re using.

For example:

Computer → HDMI cable → Monitor HDMI port

The monitor should be set to the corresponding HDMI input.

3. Check and Reseat the Display Cable

A loose cable is one of the simplest possible causes of a no-signal problem.

Turn off the computer and, if appropriate, the monitor before checking the connection.

Then:

1. Disconnect the display cable.
2. Inspect both connectors.
3. Check for visible damage.
4. Reconnect the cable firmly.
5. Make sure it is fully inserted on both ends.
6. Turn the equipment back on.
7. Check the display again.

If you have another compatible cable available, test it.

A damaged HDMI, DisplayPort or USB-C cable can produce intermittent or complete loss of display.

4. Try a Different Display Port

If your computer or graphics card has multiple video outputs, try another one.

For example, if HDMI output 1 produces no display, try another compatible output if available.

You can also try another port on the monitor.

This can help determine whether the problem is related to a particular port rather than the entire computer or monitor.

5. Restart the Computer and Monitor

A complete restart can resolve temporary display or graphics problems.

Try this:

1. Turn off the computer.
2. Turn off the monitor.
3. Wait for a short period.
4. Turn the monitor back on.
5. Start the computer.
6. Wait for Windows or macOS to load.
7. Check whether the display returns.

If the display appears during startup but disappears once the operating system loads, the problem may involve display settings or graphics drivers.

6. Check Whether the Computer Is Actually Starting

Sometimes the monitor isn’t the real problem.

The computer may not be completing its startup process.

Check for signs such as:

• Power lights
• Fan activity
• Keyboard lights
• Startup sounds
• Drive activity
• Motherboard indicator lights

If the computer doesn’t appear to start normally, the problem may be related to the computer hardware rather than the monitor.

7. Check Whether the Cable Is Connected to the Correct Graphics Output

Desktop computers with a dedicated graphics card can have video outputs in two different areas.

You may have video ports on:

• The dedicated graphics card
• The motherboard

If a dedicated graphics card is installed, the monitor may need to be connected to the appropriate graphics-card output.

Check where the display cable is plugged in.

If you’re unsure which port should be used, check the computer or graphics-card documentation rather than repeatedly moving cables between ports.

8. Check Windows Display Settings

If you can see the display during startup but lose the picture once Windows loads, display settings could be involved.

Windows provides options for:

• Display resolution
• Multiple monitors
• Refresh rate
• Display arrangement
• Which screen is being used

If you have more than one monitor connected, Windows may be sending the display to another screen.

You can also try the Windows display shortcut:

Windows key + P

This allows you to switch between display modes such as:

• PC screen only
• Duplicate
• Extend
• Second screen only

Choose the appropriate option for your setup.

9. Reset the Graphics Output

If Windows appears to be running but the screen remains blank, you can try resetting the graphics driver.

On Windows, press:

Windows key + Ctrl + Shift + B

The screen may briefly flicker or go dark while Windows resets the graphics driver.

If the computer responds and the display returns, a temporary graphics-driver issue may have been involved.

10. Check the Graphics Card

If your computer uses a dedicated graphics card, the card or its connection can potentially cause a no-signal problem.

Check whether:

• The graphics card is seated correctly.
• The required power connectors are connected.
• The fans or indicator lights behave normally, where applicable.
• The display cable is connected to the graphics card.
• Another compatible output is available for testing.

Important: If you’re not comfortable opening a desktop computer, don’t remove or reseat internal hardware yourself.

A technician can safely inspect the graphics card and other internal components.

11. Check the Monitor With Another Device

One of the most useful troubleshooting tests is to connect the monitor to another compatible device.

For example, you could test it with:

• Another computer
• Laptop
• Game console
• Other compatible video source

If the monitor works with another device

The monitor is less likely to be the problem.

You can then investigate the original computer, graphics output, cable or settings.

If the monitor still shows “No Signal”

The problem could involve:

• The monitor
• Cable
• Input selection
• Monitor port
• Compatible adapter

This simple test can help narrow down the cause considerably.

12. Test the Computer With Another Monitor

If another monitor is available, connect it to the computer.

If the second monitor works

The original monitor, cable or input connection may be responsible.

If the second monitor also shows no signal

The problem is more likely to involve the computer, graphics card, output port, RAM or another hardware component.

Testing both sides can help identify where the fault is located.

13. Check RAM and POST Indicators

If the computer powers on but produces no display, the startup process may not be completing successfully.

Some desktop computers provide diagnostic indicators or beep codes that can help identify hardware problems.

Depending on the motherboard, these may indicate issues involving:

• RAM
• CPU
• Graphics
• Boot devices
• Other hardware

If you’re comfortable with PC hardware, you can check the manufacturer’s documentation for the meaning of the diagnostic indicators.

If you’re not comfortable opening the computer, it’s safer to have a technician inspect it.

14. Check DisplayPort and USB-C Connections

DisplayPort and USB-C connections can introduce additional troubleshooting variables.

For example, a USB-C port may not necessarily support video output simply because it physically accepts a USB-C connector.

Likewise, DisplayPort adapters can have compatibility limitations.

If you’re using an adapter, docking station or USB-C connection:

• Check that the port supports video output.
• Confirm that the adapter is compatible.
• Try a direct connection where possible.
• Test another cable or adapter.
• Check whether the computer recognises the external display.

A direct connection can help determine whether the adapter or dock is contributing to the problem.

15. Check Resolution and Refresh Rate

An unsupported display configuration can sometimes result in a blank screen or display problem.

If you can access Windows through another display, check:

Settings → System → Display

Review the:

• Resolution
• Refresh rate
• Multiple-display configuration

If the problem started immediately after changing display settings, returning to a supported configuration may resolve it.

For advanced display configurations, check the monitor manufacturer’s recommended resolution and refresh-rate specifications.

16. What If the Screen Goes Black After Windows Starts?

This situation is slightly different from having no display from the beginning.

If you can see:

• The manufacturer’s logo
• BIOS/UEFI
• Windows startup

but the screen becomes blank afterward, the hardware may be capable of producing a display signal.

Possible causes can include:

• Graphics driver problems
• Incorrect resolution
• Unsupported refresh rate
• Windows display configuration
• Multiple-monitor settings

Try the Windows display shortcuts and graphics reset described above.

If the problem began after a driver or display-setting change, additional Windows troubleshooting may be necessary.

17. Try Another Cable or Adapter

If you’ve checked the monitor, computer and input settings but the display still isn’t working, test another compatible cable.

This is particularly useful for:

• HDMI
• DisplayPort
• USB-C
• USB-C video adapters
• Display adapters
• Docking stations

A cable can look perfectly normal while still failing to transmit a reliable video signal.

If the display works immediately after changing the cable, you’ve found an important clue.

Advanced Troubleshooting

The following steps involve computer hardware or firmware and are not recommended for everyone.

If you are not comfortable working inside a computer, stop here and get professional assistance.

Check Internal Connections

A desktop computer may have loose internal connections affecting the graphics card, RAM or power supply.

A technician can inspect:

• RAM modules
• Graphics card seating
• Power connectors
• Motherboard connections
• Diagnostic indicators

Avoid opening the computer if doing so could create a safety or warranty concern.

Check BIOS/UEFI

If the computer produces no display even before Windows starts, BIOS/UEFI-level troubleshooting may be appropriate.

Depending on the hardware, this can include checking:

• Primary display settings
• Integrated vs dedicated graphics
• Hardware detection
• Diagnostic messages

BIOS/UEFI settings should only be changed when you understand what the setting controls.

Check for Hardware Faults

If the monitor, cables and ports have been tested and the computer still produces no display, the problem could involve hardware such as:

• Graphics card
• RAM
• Motherboard
• Power supply
• CPU
• Monitor

At this point, replacing random components can become expensive and may not identify the actual fault.

Professional diagnosis can be more appropriate.

How to Tell Whether the Monitor or Computer Is the Problem

A few simple tests can help narrow down the fault.

This approach is generally more useful than replacing hardware without first identifying where the problem occurs.

When Should You Contact an IT Technician?

Professional help may be appropriate if:

• Your monitor remains blank after basic troubleshooting.
• Multiple monitors show no signal.
• The computer appears to start but never produces a display.
• The problem involves a graphics card or internal hardware.
• The issue began after a hardware change.
• You suspect a motherboard, RAM or power-supply problem.
• You aren’t comfortable opening the computer.
• You have already tried different cables and displays without finding the cause.

For a business computer, getting the problem diagnosed properly can also help avoid unnecessary downtime.