Computer Turns On but Monitor Says No Signal? 8 Fixes to Try

If your computer powers on but the monitor says “no signal,” the problem is usually somewhere between the display input, video cable, graphics output, and Windows—not necessarily the monitor itself. Work through these checks in order before replacing hardware or opening the computer.

Start with the monitor and cable

1. Confirm the monitor has power and the right input selected. Make sure the monitor’s power light is on, then use its Input or Source button to select the connection you are actually using—such as HDMI, DisplayPort, or DVI. A monitor can be working perfectly while listening to the wrong input.


2. Reconnect the video cable at both ends. Turn the monitor and computer off, unplug the cable, and reconnect it firmly. Look for a loose plug, bent connector, damaged cable, or adapter that is not seated correctly. Do not force a connection.


3. Use the correct video output on the computer. If the computer has a separate graphics card, the monitor usually needs to connect to the ports on that card rather than the ports grouped with the USB and network connectors on the motherboard. Compare the current port with the other video outputs on the back of the PC.


4. Test one part at a time. Try a known-good cable, a different video port, or the monitor with another computer. If possible, connect just one monitor directly to the computer and temporarily remove docks, splitters, adapters, and extra displays.

If your setup uses HDMI and testing points to the cable, compare certified HDMI cables.For a related troubleshooting path, see Computer Won’t Turn On? 9 Safe Checks to Try First.

Check the Windows display path

5. Restart both devices. Turn off the computer and monitor, wait a few seconds, then start the monitor first and the computer second. A clean restart can restore the connection after a sleep, update, or dock issue.


6. Ask Windows to detect the display. If you can see another screen, open Settings > System > Display, expand Multiple displays, and choose Detect. Use this only after the cable and input checks, because Windows cannot detect a display that is not receiving a usable signal.


7. Reset the graphics driver. When the computer seems to be running but the display is still blank, press Windows + Ctrl + Shift + B. Windows may beep or the screen may flicker as it resets the graphics driver. If nothing changes, restart the computer.

When the problem may be inside the computer

8. Stop and get help if there is no picture even before Windows loads. If the monitor shows no signal with known-good cables and another monitor, and you never see a manufacturer logo or setup screen, the issue may involve the graphics card, memory, power supply, or another internal component. Do not open the case unless you are comfortable working safely with computer hardware.

Separate a display issue from a power issueIf the computer’s lights, fans, or keyboard indicators come on, treat the monitor as its own device first. Check its power cord, input source, brightness, and the video cable at both ends. Test a different port, cable, or display only after noting the original connection. If there are no signs of power anywhere, begin with the outlet and power checks in our related computer power guide instead of focusing on the monitor.

Computer on but monitor says no signal: quick answers

Why does my monitor say no signal when the PC is on?

The monitor is not receiving usable video from the selected input. Common causes are the wrong source setting, a loose or faulty cable, an incorrect graphics port, an incompatible adapter, or a graphics driver problem.

Should I plug my monitor into the motherboard or graphics card?

When a desktop has a separate graphics card, connect the monitor to the ports on that card unless the computer maker specifically directs otherwise. The motherboard video ports may be disabled or may use a different graphics system.

Can a bad HDMI cable cause no signal?

Yes. A damaged or incompatible cable can prevent a monitor from receiving video. Testing a known-good cable is one of the fastest ways to rule it out.

Helpful Microsoft resources

• Troubleshoot external monitor connections in Windows


• Troubleshoot blank screens in Windows


• How to use multiple monitors in Windows

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