Start with the power cable and outlet

A monitor that won't turn on usually isn't broken—it's disconnected or receiving no power. Before you assume the display itself has failed, check the physical connections first, because this solves the problem in most cases.

Locate the power cable where it plugs into the back of the monitor. Push it in firmly; cables work loose from vibration, bumps, or being moved. If it's already tight, unplug it completely, wait five seconds, and plug it back in. This resets the monitor's internal power circuit.

Next, test the outlet itself. Plug a lamp, phone charger, or another device into the same outlet to confirm it has power. If nothing works in that outlet, try a different one on the same wall or in another room. If the outlet is dead, you may have a tripped breaker or a failed outlet—not a monitor problem.

Key Takeaways

  • Check the power cable connection at the monitor first, then test the outlet with another device to rule out power supply issues.
  • Press the power button on the monitor itself for at least one second; some monitors require a deliberate press rather than a tap.
  • Look for a small LED light on the monitor's frame or bezel—if it's off, the monitor has no power; if it's on, the problem is likely the cable to your computer.
  • Swap the video cable (HDMI, DisplayPort, or USB-C) with a known working cable to test whether the monitor receives a signal from your computer.
  • If the monitor powers on but shows no picture, restart your computer and check that the correct input is selected on the monitor's menu.

Press and hold the power button

The monitor's power button is usually on the front bezel, bottom center, or along one edge. Press it firmly and hold it for at least one full second. Some monitors, especially older ones, require a deliberate press rather than a quick tap to turn on.

While you hold the button, watch for a light to appear on the monitor's frame. Many monitors have a small LED—often white, blue, or amber—that glows when power reaches the unit. If the LED lights up but the screen stays black, the monitor is receiving power but not receiving a video signal from your computer. If the LED does not light at all, the monitor is not getting power, and you need to revisit the cable and outlet.

Check the video cable connection

A monitor needs two separate cables: one for power and one to carry the picture from your computer. The power cable gets the monitor running; the video cable carries the image. If power reaches the monitor but the screen stays dark, the video cable is likely the problem.

Look at the back of the monitor for the video input ports. Most monitors have HDMI, DisplayPort, USB-C, or older VGA and DVI ports. Locate which cable is plugged in and trace it back to your computer. Unplug the video cable from both the monitor and the computer, wait a few seconds, and plug it back in firmly at both ends. Make sure it clicks or seats completely—a loose video cable will produce no picture even though the monitor is powered on.

If you have a spare video cable of the same type, swap it in to test whether the original cable is faulty. Video cables can fail internally even though they look fine on the outside. If a different cable produces a picture, the original cable is damaged and needs replacement.

Verify the correct input is selected

Monitors with multiple input ports can only display from one at a time. If your computer is plugged into HDMI but the monitor is set to DisplayPort, you will see a black screen even though everything is connected correctly.

Look for an Input or Source button on the monitor's bezel, usually near the power button. Press it to open the input menu on the screen. Select the input that matches your cable—HDMI 1, HDMI 2, DisplayPort, USB-C, or whatever port your cable is plugged into. The correct input will usually show a picture when ready.

If you are not sure which input your cable uses, check the connector itself. HDMI is flat and rectangular with a notch. DisplayPort is smaller and rectangular with a clip. USB-C is small and oval. VGA is three rows of holes. DVI is rectangular with a flat edge on one side. Match the shape to the label on the monitor's input menu.

Restart your computer and check the display settings

If the monitor is powered on and set to the correct input but still shows no picture, the problem may be on the computer side. Restart your computer completely—shut it down, wait ten seconds, and turn it back on. During startup, you should see the computer's boot screen appear on the monitor. If it does, the monitor is working and the issue is with how Windows or macOS is sending the picture.

Once your computer finishes starting up, check your display settings. On Windows, right-click the desktop and select Display settings. On Mac, open System Preferences and go to Displays. Look for an option to detect or connect displays. Sometimes a computer stops sending a signal to a monitor after sleep mode or an update, and manually detecting the display will restore the picture.

If you have a laptop, you may need to press a keyboard shortcut to switch the display output. On many laptops, holding Fn and pressing F5, F7, or F8 (depending on the brand) will cycle through display modes: laptop screen only, external monitor only, or both. Check your laptop's manual or search online for "[your laptop model] display shortcut" to find the exact key combination.

Test with a different computer or device

If you have access to another computer, laptop, or device with the same type of video output, connect it to the monitor using the same cable. If the second device produces a picture, your monitor is working and the problem is with your original computer's graphics output or settings. If the second device also produces no picture, the monitor itself is likely faulty and may need service or replacement.

You can also test a phone or tablet if your monitor has USB-C input. Many modern monitors accept USB-C video signals from phones and laptops. Plug your phone into the USB-C port and check whether the monitor detects it. This is a quick way to confirm the monitor's video circuitry is working.

Check for a faulty graphics card or port

If the monitor works with a different computer but not with yours, the problem is likely your computer's graphics output. Desktop computers have a graphics card (either built into the motherboard or installed separately) that sends the picture to the monitor. Laptops have built-in graphics hardware.

First, try a different video port on your computer if it has more than one. Many computers have both HDMI and DisplayPort, or multiple HDMI ports. Unplug your cable and try another port. If a different port works, the original port is faulty but your graphics hardware is fine.

If all ports fail, restart your computer in Safe Mode (on Windows, restart and press F8 or Shift+F8 during startup; on Mac, restart and hold Shift). Safe Mode loads only essential drivers. If the monitor works in Safe Mode, a software driver or background program is interfering with your display. If it still does not work in Safe Mode, the graphics hardware itself may be failing and you may need to contact the computer manufacturer or a repair technician.

Frequently Asked Questions

Why does my monitor have power but no picture?

The video cable is likely loose, plugged into the wrong input, or faulty. Unplug and reseat the video cable at both ends, then check that the monitor's input is set to match the cable type. If that does not work, try a different video cable or test the monitor with another computer to confirm the cable or computer is the problem.

Can a monitor break from being turned off for a long time?

No. Monitors can sit unplugged for months or years and still work when powered on again. If a monitor does not turn on after storage, the issue is almost always a loose cable or a tripped outlet, not damage from sitting idle.

What does the LED light on my monitor mean?

A lit LED means the monitor is receiving power. The color and behavior vary by brand—white usually means normal operation, amber or orange often means standby or sleep mode, and no light means no power. Check your monitor's manual for the specific meaning of each color.

Should I unplug my monitor when I am not using it?

It is not necessary. Modern monitors use very little power in standby mode. Unplugging is safe but offers no real benefit unless you want to reduce power consumption or are storing the monitor for a long time.

What if my monitor turns on for a second then goes black?

This usually means the monitor is entering sleep mode because it is not receiving a video signal. Check that your computer is powered on and that the video cable is fully seated. Restart your computer to force it to send a signal to the monitor. If the problem persists, try a different video cable or test the monitor with another computer.