How to Fix a Computer Screen: Troubleshooting Steps for Common Problems

Start with the simplest fixes first

Most computer screen problems can be solved without opening your machine or calling for help. Before you assume the screen is broken, check whether the monitor is powered on, whether the cable connecting it to your computer is loose, and whether your brightness setting has been turned all the way down. These three things account for the majority of "broken screen" calls. If your screen is completely black but you can hear your computer running, the monitor itself may not be receiving power — look for a power button on the monitor frame (usually at the bottom or side) and press it, then check that the power cable is plugged into both the monitor and the wall outlet.

If the monitor is on but the image is dim, look for brightness and contrast buttons on the monitor itself — these are often small buttons near the power button, sometimes with a sun icon. Press the brightness button repeatedly until the image becomes visible. On some monitors, you may need to hold the button for a few seconds rather than tap it. If you have adjusted the brightness and the screen is still too dark, the problem may be in your computer's display settings rather than the monitor hardware.

Key Takeaways

Check that the monitor is powered on and that the cable connecting it to your computer is firmly seated in both the monitor and the computer port.
Adjust the brightness and contrast controls on the monitor itself using the buttons on the monitor frame, not your keyboard.
Restart your computer completely — power it off, wait 30 seconds, then power it back on — before assuming the screen hardware is damaged.
If the screen shows an image but it is distorted, flickering, or discolored, the problem is usually a loose cable or an outdated graphics driver rather than a broken monitor.
Replacing a monitor costs between $100 and $400 for a standard display, but most screen problems can be fixed for free by adjusting settings or reseating cables.

Reseat the cable connecting your monitor to your computer

A loose video cable is one of the most common causes of a blank or flickering screen. The cable that runs from your monitor to your computer can work itself loose over time, especially if your desk gets bumped or moved. Locate where the cable plugs into the back of your computer — it will be a thick cable with a connector that has either 15 small holes (for older VGA cables) or a flat rectangular shape (for HDMI or DisplayPort cables). Gently pull the cable straight out, wait five seconds, then push it back in firmly until you hear or feel a click. If the connector has small screws on either side, tighten them by hand.

Do the same at the monitor end — unplug the cable from the monitor, wait a few seconds, and plug it back in. Make sure the cable is not kinked or bent sharply, as this can damage the wires inside. If you have a spare video cable of the same type, try plugging that in instead — this will tell you whether the problem is the cable itself or the connection points. A damaged cable will need to be replaced, but a loose connection usually fixes the problem when ready.

Restart your computer completely

Before you assume the screen hardware is damaged, restart your computer from a complete shutdown. Do not use sleep mode or restart — power the computer off entirely, wait 30 seconds, then power it back on. This clears temporary display settings and resets the connection between your computer and monitor. Many screen problems, including flickering, color distortion, and partial image loss, are caused by a software glitch that a full restart will fix.

If you cannot see the screen well enough to use the mouse or keyboard, hold down the power button on your computer for 10 seconds until it shuts off completely. Wait 30 seconds, then press the power button again to turn it back on. Once the computer has fully restarted, check whether the screen image has returned to normal.

Check your graphics driver and display settings

If your screen is showing an image but it looks wrong — colors are off, the image is stretched or squeezed, or the resolution is too low — the problem is usually in your display settings or graphics driver rather than the monitor itself. On Windows, right-click on an empty area of your desktop and look for an option that says "Display settings" or "Graphics settings." On Mac, go to System Preferences and select "Displays." In these menus, you can adjust the resolution (the number of pixels displayed) and the refresh rate (how many times per second the image updates).

If the image looks blurry or pixelated, try changing the resolution to match your monitor's native resolution — this information is usually printed on a sticker on the back of the monitor or listed in the monitor's manual. If you do not know the native resolution, set it to the highest number available. If the screen is flickering, try lowering the refresh rate from 60 Hz to 50 Hz or raising it to 75 Hz — the right setting depends on your monitor model. If changing these settings does not help, your graphics driver may be outdated. Visit the website of your graphics card manufacturer (NVIDIA, AMD, or Intel) and read the latest driver for your specific card model.

Test with a different monitor or video port

If you have access to another monitor, connect it to your computer using the same cable and port. If the second monitor displays an image correctly, the problem is with your original monitor, not your computer. If the second monitor also shows no image or a distorted image, the problem is likely with your graphics card or the video port on your computer. If you have a laptop, try connecting an external monitor to see whether the built-in screen or the video output is the problem.

Some computers have more than one video port on the back — you might see HDMI, DisplayPort, and VGA ports all available. Try unplugging your monitor from one port and plugging it into a different port, then restarting your computer. This will tell you whether a specific port is damaged or whether the problem affects all video outputs. If a different port works, the original port may need to be repaired by a technician.

Identify physical damage and when to replace the monitor

If your screen has visible cracks, dark spots that do not go away after a restart, or areas where the image is permanently missing, the monitor itself is damaged and will need to be replaced. A cracked screen cannot be repaired cost-effectively — replacement monitors for desktop computers typically cost between $100 and $400 depending on size and features. Before you buy a replacement, note the size of your current monitor (usually 21 to 27 inches for desktop screens) and the type of connector it uses (HDMI, DisplayPort, or VGA).

If your monitor is very old and uses a VGA connector (a cable with 15 small holes), you may need to buy a new cable as well as a new monitor, since most modern monitors use HDMI or DisplayPort. When you purchase a replacement, make sure it has the same type of connector as your computer's video port, or buy an adapter cable to bridge the difference. If you are unsure whether your monitor is worth replacing or whether the problem is actually with your computer, take it to a local computer repair shop — they can test it with different cables and computers to pinpoint the cause.

Frequently Asked Questions

Why is my screen black even though my computer is on?

Check that the monitor power button is pressed and the power cable is plugged in. Then verify that the video cable connecting the monitor to your computer is fully seated at both ends. If both are connected, restart your computer completely. If the screen remains black after restart, try connecting a different monitor to see whether the problem is the monitor or the computer's video output.

What should I do if my screen is flickering?

First, check that the video cable is not loose or kinked. Then restart your computer. If flickering continues, go to your display settings and try adjusting the refresh rate — lower it to 50 Hz or raise it to 75 Hz depending on what your monitor supports. If the problem persists, update your graphics driver by visiting the manufacturer's website and downloading the latest version for your card model.

Can I fix a cracked monitor screen?

No — a cracked screen cannot be repaired cost-effectively. The entire panel would need to be replaced, which costs nearly as much as buying a new monitor. If your screen is cracked, replacement is the only option. A new monitor typically costs $100 to $400 depending on size and features.

How do I know if the problem is my monitor or my graphics card?

Connect a different monitor to your computer using the same cable and port. If the second monitor works, your original monitor is the problem. If the second monitor also does not work, the issue is likely your graphics card or video port. You can also try connecting your monitor to a different computer — if it works there, your monitor is fine and the problem is with your original computer.

What is the difference between HDMI, DisplayPort, and VGA cables?

These are three different types of video cables. HDMI and DisplayPort are modern standards used on newer computers and monitors. VGA is an older standard with 15 small holes in the connector. Check what type of port your monitor and computer have — they must match, or you will need an adapter cable. Most new monitors use HDMI or DisplayPort.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.