Start with the simplest fixes first
A blank screen usually means one of three things: the monitor is off, the cable is loose, or the computer itself isn't running. Before you assume hardware failure, check these in order. Most screens that won't turn on are actually on but receiving no signal — which is fixable in seconds.
Look at the monitor's power button. It should have a small light next to it — green means it's on, amber or no light means it's off. Press the button and wait five seconds. If nothing happens, check that the power cable is plugged into both the back of the monitor and the wall outlet. A loose connection here is the single most common reason a screen appears dead.
Key Takeaways
- Check the monitor's power button and the power cable connection to the wall outlet before assuming the computer has failed.
- Verify the video cable (HDMI, DisplayPort, or VGA) is fully seated in both the monitor and the computer's video port.
- Restart the computer by holding the power button for ten seconds, then wait 30 seconds before pressing it again to turn it back on.
- If the monitor shows a "no signal" message, the computer is running but not sending video — try a different video cable or port.
- Disconnect external devices like USB drives and printers, then restart, because a faulty device can sometimes prevent the computer from booting normally.
Check the video cable connection
The cable that runs from your monitor to your computer carries the picture signal. If it's loose or damaged, you'll see a blank screen even though the monitor is powered on. Look at both ends of this cable — it's usually HDMI (a flat rectangular connector), DisplayPort (smaller and rectangular), or VGA (a blue connector with three rows of holes).
Unplug the cable from the back of the monitor, wait three seconds, and plug it back in firmly. You should feel it click or seat completely. Do the same at the computer end. If the screen still shows nothing, try a different video cable if you have one available — the original cable may be damaged internally even though it looks fine.
On laptops, there's no separate monitor cable, so skip this step. On desktop computers with multiple video ports on the back, try plugging the cable into a different port. Some computers have both integrated graphics and a separate graphics card, and the monitor needs to be connected to whichever one is active.
Restart the computer properly
Your computer might be running but frozen or in sleep mode. Hold down the power button on the computer itself for ten full seconds — don't just tap it. This forces the computer to shut down completely. Wait 30 seconds, then press the power button once to turn it back on. Listen for fan noise or look for lights on the computer case that indicate it's booting.
If you hear the computer running but the screen stays blank, the computer is likely starting up. Wait two to three minutes without touching anything — some computers take longer to boot than others, especially if they're updating or running a disk check. During this time, the monitor may show "no signal" or stay black, which is normal.
If the screen comes to life during startup but then goes blank again, the computer may be reaching the login screen. Try moving the mouse or pressing a key — sometimes the screen goes dark to save power and wakes up when you interact with it.
Disconnect external devices and try again
A faulty USB device, external hard drive, or printer connected to your computer can sometimes prevent it from starting normally. Unplug everything except the keyboard, mouse, and monitor. This includes USB flash drives, external hard drives, printers, and any other peripherals.
Now restart the computer again using the power button method described above. If the screen comes on this time, one of the devices you unplugged was causing the problem. Plug them back in one at a time, restarting after each one, until you find which device is causing the issue. That device may need to be replaced or its drivers updated.
Look for error messages or lights on the computer
While the screen is blank, pay attention to what the computer itself is doing. Look at the power button and any other lights on the case — they should be on or blinking. Listen for fan noise. If you hear nothing and see no lights, the computer itself isn't getting power, which means checking the power cable to the wall outlet and the power supply switch on the back of the case (if your computer has one).
Some computers show error codes as beeping sounds or LED patterns when something is wrong. A single beep usually means the computer is starting normally. Repeated beeps or a pattern of beeps indicates a hardware problem — write down the pattern and search for your computer model plus "beep codes" to find what it means.
If the monitor shows text like "no signal," "out of range," or "check cable," the monitor is working but the computer isn't sending video. This is different from a completely blank screen and usually points to a video cable or port problem rather than a failed component.
When to suspect a hardware failure
If you've checked the power cables, restarted the computer, and tried different video cables, but the screen remains blank and you hear no fan noise or see no lights on the computer, a hardware component may have failed. The most common culprits are the power supply, the motherboard, or the graphics card.
Before concluding hardware failure, try one more thing: unplug the computer from the wall outlet completely, wait 30 seconds, and plug it back in. This clears the power supply's memory and sometimes fixes startup issues. Press the power button and wait three minutes.
If the screen still won't turn on and the computer shows no signs of life, the computer likely needs professional repair or component replacement. Contact the manufacturer's support line or take it to a repair shop. Have ready the computer's model number (usually on a sticker on the case) and a description of what you've already tried.
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 fully plugged in at both ends, and try restarting the computer. If the message persists, try a different video cable or a different video port on the back of the computer.
The screen was working fine yesterday and now it's blank — what changed?
Check whether you plugged in any new USB devices, external drives, or peripherals yesterday. Unplug them and restart. Also check that the monitor's power cable didn't get bumped loose — this happens surprisingly often near desks where people move things around.
My laptop screen is black but I can see the keyboard lights are on — is it just in sleep mode?
Probably. Press any key or move the mouse. If the screen wakes up, it was in sleep mode. If it stays black, hold the power button for ten seconds to shut it down completely, wait 30 seconds, and press the power button once to restart.
I tried everything and the screen is still blank — what's my next step?
Contact the computer manufacturer's support line with your model number and describe what you've tried. They can walk you through more advanced troubleshooting or arrange a repair. If the computer is out of warranty, a local repair shop can diagnose the problem for a fee.
Is it safe to keep restarting the computer if the screen won't turn on?
Yes. Restarting by holding the power button is a standard troubleshooting step and won't damage the computer. However, if you restart more than three times without success, stop and let the computer sit for an hour before trying again — this gives the power supply time to cool down if it's overheating.