Start with the simplest fixes first

Most monitor problems come from loose cables, power issues, or settings you can change in seconds. Before you assume the monitor is broken, check that the power cable is plugged firmly into both the monitor and the wall outlet, and that the monitor's power button is actually on. If the screen is dark but you hear the monitor humming, the display cable between your computer and monitor may be loose — unplug it from both ends and plug it back in firmly. These three steps fix the majority of monitor problems.

If the monitor still does not respond, try a different power outlet to rule out a dead circuit. If you have a second monitor or a TV with an HDMI cable, connect it to your computer to confirm the computer itself is working. This tells you whether the problem is the monitor or the computer sending the signal.

Key Takeaways

  • Check the power cable connection at both the monitor and wall outlet, and make sure the power button is pressed on.
  • Unplug and reseat the display cable (HDMI, DisplayPort, or VGA) at both the monitor and computer end.
  • Test with a different power outlet and a second monitor if you have one to narrow down whether the problem is the monitor or the computer.
  • Adjust brightness and contrast dials on the monitor itself, as a turned-down brightness knob looks like a dead screen.
  • If the monitor powers on but shows no image after 30 seconds, restart your computer with the monitor plugged in and powered on.

Check the brightness and contrast controls

Many monitors have physical dials or buttons on the front or side that control brightness and contrast. If the brightness is turned all the way down, the screen will appear completely black even though the monitor is working. Look for a dial or button labeled "brightness" or showing a sun symbol, and turn it up slowly while watching the screen. You should see an image appear.

The contrast dial works similarly — if it is set too low, the image will be very faint. Adjust it until you can see text and images clearly. These controls are straightforward to bump accidentally, especially if the monitor sits in a tight space or if someone else uses your desk.

Restart your computer with the monitor powered on

Sometimes the computer stops sending a signal to the monitor even though both devices are powered on. Shut down your computer completely — do not just put it to sleep. While the computer is off, make sure the monitor is powered on and the cable is plugged in. Then turn the computer back on and wait 30 seconds for it to fully boot before expecting an image.

If you see the startup screen or login screen appear, the monitor and computer connection is working. If the screen stays black, the problem is either the display cable or the graphics hardware inside the computer.

Swap or test the display cable

The cable that connects your monitor to your computer can wear out, get pinched, or come loose. The most common types are HDMI (flat rectangular connector), DisplayPort (smaller rectangular connector with a clip), and VGA (blue connector with three rows of holes). Unplug the cable from the back of the monitor first, then from the computer. Look at both ends for bent pins, frayed wires, or visible damage.

Plug the cable back in firmly — you should feel a click or resistance. If you have a second cable of the same type, try that one instead. If a different cable makes the monitor work, the original cable is damaged and needs to be replaced. If the monitor still does not work with a new cable, the problem is likely inside the monitor or the computer's graphics port.

Test the monitor on a different computer

If you have access to a laptop, desktop, or another device with the same type of display port, connect your monitor to it using the same cable. If the monitor works on the other computer, your monitor is fine and the problem is with your original computer's graphics card or display port. If the monitor stays dark on the second computer too, the monitor itself needs repair or replacement.

This test is the clearest way to know which device is causing the problem. Many computer repair shops will do this test for free if you bring the monitor in, so you do not have to own a second computer to find out.

Check for signs of physical damage or overheating

Look at the monitor's vents and the area around the power cable for dust buildup, which can cause overheating. If the monitor was working and suddenly went dark, it may have shut itself off due to heat. Unplug it, wait 10 minutes, and plug it back in. If it works again, dust is likely the problem — use a dry cloth or compressed air to gently clean the vents on the back and sides.

If you see burn marks, melted plastic, a strong smell, or liquid damage, do not plug the monitor back in. These are signs of internal electrical failure and the monitor should not be used. Physical damage to the screen itself (cracks, dark spots that do not go away, or lines) usually means the monitor needs replacement, as these parts cannot be repaired at home.

Adjust display settings on your computer

If the monitor powers on and the cable is connected but the image looks wrong — too dark, too small, stretched, or upside down — the problem may be in your computer's display settings rather than the monitor itself. Right-click on your desktop and look for an option like "Display settings" or "Graphics properties." From there you can adjust resolution, refresh rate, and orientation.

If you accidentally set the resolution too high or too low, the image may look distorted or tiny. Set it back to the recommended resolution for your monitor, which is usually listed in the monitor's manual or on the manufacturer's website. If you turned the display upside down or sideways by accident, you can rotate it back in the same settings menu.

Frequently Asked Questions

Why is my monitor screen completely black but the power light is on?

The brightness dial is likely turned all the way down. Look for a brightness control on the monitor's front or side and turn it up. If that does not work, check that the display cable is plugged in firmly at both ends. If the cable is find and brightness is up, restart your computer with the monitor powered on and wait 30 seconds for the image to appear.

What does it mean if my monitor shows "no signal" or "input not detected"?

This message means the monitor is powered on and working, but it is not receiving a picture from the computer. Unplug the display cable from both the monitor and computer, then plug it back in firmly. If that does not work, try a different cable of the same type. If a different cable works, the original cable is damaged.

Can I fix a monitor with a cracked screen myself?

No. A cracked or shattered screen cannot be repaired at home and the monitor should not be used, as broken glass can cause injury. The screen panel is fused to the monitor's internal components and replacing it costs nearly as much as buying a new monitor. In most cases, replacement is the only option.

My monitor worked fine yesterday but now it will not turn on at all. What should I check?

First, try a different power outlet to rule out a tripped circuit breaker. Then check that the power cable is plugged in firmly at both the monitor and the wall. If the monitor still does not power on, the power supply inside the monitor may have failed. If you have a second monitor, connect it to your computer to confirm the computer is still working.

Is it safe to open up a monitor and try to fix it myself?

No. Monitors contain high-voltage capacitors that can hold a dangerous electrical charge even after the power is unplugged. Opening a monitor without proper training and equipment can cause serious injury or death. If the monitor is not under warranty and repair is not worth the cost, replacement is safer than attempting internal repairs.