Your screen is dark, but your computer might still be running
A blank screen does not always mean your computer is off. The machine itself might be powered on and working, but the display is not receiving a signal, or the monitor is in sleep mode, or the cable connecting them is loose. Before you assume the computer has failed, you need to separate the monitor problem from the computer problem — they are often different issues with different fixes.
Start by checking whether your computer is actually on. Listen for fan noise, look for lights on the case or keyboard, and try pressing a key or moving the mouse. If the keyboard lights up or the fans spin, your computer is running. If nothing happens at all, move to the power supply section below. If the computer seems to be on but the screen stays dark, work through the monitor checks in this guide.
Key Takeaways
- A dark screen usually means the monitor is not receiving power or signal, not that the computer itself has failed.
- Check the power cable at both the monitor and the wall outlet, and look for a loose cable between the monitor and computer.
- Press the monitor's power button directly — many monitors have their own on/off switch separate from the computer.
- If the monitor has a brightness dial or button, turn it all the way up to rule out accidental dimming.
- Restart the computer by holding the power button for ten seconds, then wait thirty seconds before pressing it again to power on.
Check the monitor power cable and outlet
The monitor needs its own power connection, separate from the computer. Trace the cable from the back of the monitor to the wall outlet. Make sure the cable is plugged in firmly at both ends — push it in until you feel it click or seat completely. A cable that looks plugged in but is actually loose is one of the most common reasons a screen stays dark.
Test the outlet itself by plugging in something else you know works, like a lamp or phone charger. If that device powers on, the outlet is fine. If it does not, try a different outlet in another room. If the monitor still does not light up after you move it to a working outlet, the monitor's power cable or the monitor itself may be damaged.
Look at the monitor's power cable for visible damage — cuts, fraying, or burn marks. If you see damage, do not use that cable. If the cable looks fine but the monitor still will not power on after trying multiple outlets, the monitor may need repair or replacement.
Press the monitor's power button
Monitors have their own power button, usually on the front or bottom edge. It is separate from the computer's power button. Press and hold the monitor's power button for two to three seconds. You should see a light turn on (often green or blue), and the screen should display something — even if it is just a "no signal" message.
If pressing the button does nothing and the monitor is plugged into a working outlet, the monitor itself may have failed. If the screen shows "no signal" or "no input," that is actually progress — it means the monitor is on and working, but it is not receiving video from the computer. Move to the cable connection section below.
Check the cable between the monitor and computer
The video cable carries the picture from your computer to the monitor. This cable plugs into the back of the computer on one end and the back of the monitor on the other. Locate both ends of this cable and make sure they are pushed in firmly. The connectors often have small screws or clips on the sides — if yours do, tighten them by hand.
Common video cables include HDMI (a flat rectangular connector), DisplayPort (similar to HDMI but slightly different shape), VGA (a blue connector with three rows of small holes), or USB-C. If you have multiple video ports on the back of your computer, try unplugging the cable and plugging it into a different port. Some computers have more than one video output, and the monitor might be connected to one that is not active.
If the cable looks damaged or the connectors are bent, you may need a replacement cable. These are inexpensive and available at most electronics stores. If you swap in a new cable and the screen still shows nothing, the problem is likely with the computer's video output or the monitor itself.
Restart the computer properly
If the monitor is powered on and connected but still shows no signal, restart the computer. Do not just click the restart button if you can see the screen — instead, hold down the computer's power button for ten full seconds. This forces the computer to shut down completely, even if it is frozen.
After the computer shuts down, wait thirty seconds. This pause lets the system fully discharge. Then press the power button once to turn the computer back on. Listen for the fans to start and watch for lights to come on. Give the computer two to three minutes to fully boot up before you assume something is wrong.
If you hear the computer start but the screen remains dark after three minutes, the issue is likely with the video card or display connection inside the computer, and you may need to take it to a repair shop.
Check the brightness and sleep settings
Some monitors have a brightness dial or buttons on the front or side. If the brightness is turned all the way down, the screen will appear completely black even though the monitor is on and receiving a signal. Look for a dial or buttons labeled with a sun symbol or "brightness," and turn it all the way up.
Computers also have sleep mode, which turns off the display after a period of inactivity to save power. If your computer is in sleep mode, the screen will be dark but the computer is still on. Move the mouse or press any key to wake it up. If the screen comes back to life, your computer and monitor are both working fine — you just need to adjust your sleep settings so the computer does not go dark as quickly.
What to do if nothing works
If you have checked the power cables, the monitor power button, the video cable, restarted the computer, and adjusted brightness, and the screen is still dark, the problem is likely inside the computer or the monitor itself is faulty. At this point, you have ruled out the straightforward fixes.
Before taking the computer to a repair shop, try one more thing: if you have access to a second monitor, borrow it and connect it to your computer using the same cable. If the second monitor works, your original monitor is the problem. If the second monitor also shows nothing, the issue is with your computer's video output or power supply.
Frequently Asked Questions
My monitor shows "no signal" — does that mean my computer is broken?
No. "No signal" means the monitor is working but not receiving video from the computer. Check that the video cable is firmly connected at both ends, and try restarting the computer. If a different monitor works with your computer, the original monitor's input may be set to the wrong source.
The screen was working fine, then went dark suddenly. What happened?
Check whether the monitor's brightness was accidentally turned down, or whether the computer went into sleep mode. If neither of those is the cause, restart the computer by holding the power button for ten seconds. If the screen stays dark after restart, the video cable may have come loose, or the monitor may have lost power.
Can I fix a monitor that won't turn on myself?
You can check the power cable, outlet, and connections yourself. If the monitor is plugged into a working outlet and the power button does nothing, the monitor's internal power supply has likely failed and will need professional repair or replacement. Monitors are usually cheaper to replace than to repair.
My computer is on but I only see a black screen, no "no signal" message.
A completely black screen (not "no signal") usually means the monitor is receiving power and signal but the brightness is turned all the way down. Look for brightness controls on the monitor itself and turn them up. If that does not work, restart the computer and wait three minutes for it to fully boot.
Do I need to replace my monitor or my computer?
Borrow a second monitor and connect it to your computer. If the second monitor works, your original monitor needs replacement. If the second monitor also stays dark, your computer's video output or power supply is the problem. This test takes five minutes and tells you exactly where to focus your repair effort.