Start with the simplest fixes first

Most monitor problems look serious but fix in under a minute. Before you assume the display is broken, check that the cable connecting your monitor to your computer is plugged in firmly at both ends — the monitor end and the computer end. Push each connector straight in until you hear or feel it click. If your monitor has a power cable separate from the video cable, make sure both are connected.

Next, check that your monitor is actually powered on. Look for a power button on the front or back of the monitor — it is usually a small circle or rectangle. Press it and wait three seconds. Many monitors have a small light that glows when they are on; if you do not see that light, the monitor is off. If the monitor still shows nothing after you turn it on, unplug the power cable, wait 10 seconds, and plug it back in. This resets the monitor's internal electronics and fixes many display problems.

Key Takeaways

  • Check that both the video cable and power cable are plugged in firmly at the monitor and the computer, then power the monitor off and back on.
  • If your monitor shows a "no signal" message or a blue or black screen, the video cable may be loose or plugged into the wrong port on your computer.
  • Adjust brightness and contrast using the buttons on your monitor itself, not your computer settings, because monitor controls override software adjustments.
  • If the image is blurry or the colors look wrong, check that your monitor is set to its native resolution in your computer's display settings.
  • Restart your computer completely if the display freezes or shows artifacts, because this clears the graphics memory and usually solves the problem.

Fix a "no signal" message or blank screen

When your monitor displays "no signal" or stays completely black or blue, the video cable is either loose or plugged into the wrong port. Look at the back of your computer. You will see several ports — some are labeled HDMI, some are labeled DisplayPort, and some older computers have VGA ports that look like they have three rows of small holes. Your monitor's cable plugs into one of these ports.

Unplug the video cable from your computer and plug it back in firmly. If that does not work, try a different video port on your computer. Many computers have more than one port, and sometimes one port is disabled or not working. If your computer has both an HDMI port and a DisplayPort, try switching the cable to the other one. Wait 10 seconds after you plug the cable in — monitors take a moment to detect the signal.

If you have a laptop, the video output port may be on the side or back. Laptops often have USB-C ports that can carry video; if your monitor cable is USB-C, make sure it is plugged into a USB-C port that supports video output, not just data transfer. Your laptop manual will tell you which ports support video.

Adjust brightness, contrast, and color settings on the monitor

If your monitor is showing an image but it is too dark, too bright, washed out, or the colors look wrong, do not change your computer settings first — change the monitor itself. Every monitor has physical buttons on the front or back that control brightness, contrast, and color. These buttons override anything your computer is set to do.

Look for buttons labeled with symbols: a sun or brightness icon, a circle or contrast icon, or a menu button. Press the menu button to open the monitor's on-screen display, which shows you what each button does. Use the buttons to increase brightness if the image is too dark, or decrease it if it is too bright. Increase contrast if the image looks flat or washed out. If the colors look wrong — too red, too blue, or too yellow — look for a color temperature or color mode setting in the menu and try a different option.

After you adjust the monitor, leave it alone for a few minutes. Some monitors take time to settle into the new settings. If the image still looks wrong after that, then check your computer's display settings, but start with the monitor controls first because they are the most common cause of brightness and color problems.

Fix blurry text or images

Blurry text or fuzzy images usually means your monitor is not set to its native resolution — the resolution it was designed to display. Your computer may be sending a resolution that the monitor has to stretch or shrink, which makes everything look soft or pixelated.

On Windows, right-click on the desktop and select "Display settings". Scroll down to find "Display resolution" and look at what resolution is currently selected. Next to it, you will see a dropdown menu. Click the dropdown and look for a resolution marked "recommended" — that is your monitor's native resolution. Select it and click "explore". Wait 15 seconds and then click "Keep changes" when Windows asks if you want to keep the new resolution.

On Mac, click the Apple menu, select "System Settings", then click "Displays". Look for "Resolution" and select "Scaled". Choose the option marked "Default for display" — that is your monitor's native resolution. The change takes effect when ready.

If you are using an older monitor or a projector, the native resolution may not be obvious. Try selecting the highest resolution available in the dropdown menu — that is usually the native resolution. If the image looks stretched or distorted, go back and try the next resolution down.

Restart your computer if the display freezes or shows artifacts

If your monitor shows strange lines, flickering, repeated images, or the display freezes and does not respond to mouse or keyboard input, restart your computer completely. Do not just put it to sleep — actually shut it down, wait 10 seconds, and turn it back on. This clears the graphics memory and resets the connection between your computer and monitor.

On Windows, click the Start button, click the power icon, and select "Shut down". Wait for the computer to turn off completely, then press the power button to turn it back on. On Mac, click the Apple menu, select "Shut Down", and wait for the computer to turn off. Then press the power button to restart.

If the problem happens again after you restart, the issue may be with your graphics driver — the software that controls how your computer sends images to the monitor. Check the manufacturer's website for your graphics card or your computer model and read the latest driver. Install it and restart your computer again. If freezing or artifacts continue, the monitor itself may be failing and may need to be replaced.

Check cable length and port compatibility for external monitors

If you are using an external monitor with a laptop or a desktop computer that is far from your desk, cable length matters. Video cables have a maximum distance they can carry a signal reliably. HDMI cables work well up to about 25 feet, but beyond that the signal may degrade and you may see a "no signal" message or a flickering image. DisplayPort cables can go longer — up to 50 feet — but still have limits.

If your monitor is more than 20 feet from your computer, use a DisplayPort cable instead of HDMI if your monitor and computer both support it. If you must use HDMI over a long distance, buy an HDMI cable rated for long runs — these have better shielding and cost a few dollars more. Do not use a cheap or damaged cable, because video cables are fragile and a bent connector or a pinched wire can break the signal.

Also check that your cable matches your ports. A USB-C monitor cable will not work in an HDMI port, and an older VGA cable will not work in a modern DisplayPort. If you are not sure what type of cable you have, look at the connector itself — each type has a different shape. Your monitor manual will tell you what type of cable it uses.

Replace the monitor if nothing else works

If you have tried all the steps above and your monitor still does not display an image, shows a persistent "no signal" message, or displays only a partial or distorted image that you cannot fix, the monitor itself may be failing. Monitors are not repairable in most cases — the internal electronics are sealed and replacing individual parts is not practical.

Before you buy a new monitor, confirm that the problem is actually the monitor and not your computer. Borrow another monitor from a friend or colleague, connect it to your computer using the same cable, and see if it works. If the borrowed monitor displays correctly, your original monitor is the problem. If the borrowed monitor also shows no signal or a blank screen, the problem is your computer's graphics port or graphics card, not the monitor.

When you buy a replacement monitor, look for one with the same type of video port as your computer — HDMI, DisplayPort, or USB-C. Check the size and resolution you need based on what you were using before. Most monitors come with a cable in the box, so you do not need to buy one separately unless your old cable was a special length or type.

Frequently Asked Questions

Why does my monitor say "no signal" when my computer is on?

The video cable is either loose or plugged into the wrong port on your computer. Unplug the cable and plug it back in firmly, making sure it clicks into place. If that does not work, try plugging it into a different video port on your computer — most computers have more than one.

How do I know if my monitor is broken or if it is my computer?

Borrow another monitor and connect it to your computer with the same cable. If the borrowed monitor works, your monitor is broken. If the borrowed monitor also does not work, the problem is your computer's graphics port or graphics card, not the monitor.

Can I fix a monitor that shows lines or flickering on the screen?

Restart your computer completely — shut it down, wait 10 seconds, and turn it back on. This clears the graphics memory and fixes most flickering or line problems. If the problem returns, read the latest graphics driver from your computer or graphics card manufacturer's website and install it.

What should I do if my monitor is too dark or too bright?

Use the brightness button on the monitor itself, not your computer settings. Look for buttons on the front or back of the monitor with a sun or brightness symbol. Press the menu button to open the on-screen display if you are not sure which button controls brightness, then adjust it until the image looks right.

Is it worth repairing a monitor, or should I just buy a new one?

Monitors are almost never worth repairing because the cost of parts and labor is usually close to or more than the cost of a new monitor. If your monitor is under warranty, contact the manufacturer about a replacement. If it is out of warranty, buying a new monitor is almost always the better choice.