Monitor Says "No Signal"? How to Fix It Step by Step

"No signal" means the monitor is on but isn't getting a picture from the computer. Common causes are the wrong input selected, a loose cable, the cable in the wrong port, or a second cable confusing it. If the monitor works with a different computer, the problem is the original computer.

Fixes to try (easiest first)

Select the right input source
Use the monitor's menu to pick the input that matches the port your cable is plugged into (for example HDMI 2). [1]
Use only one video cable
With two video cables connected, the monitor can look for a signal on the wrong one. [1]
Reseat or replace the cable
Unplug and firmly reconnect both ends. Replace the cable if it's damaged. [1]
Plug into the graphics card, not the motherboard
On desktops with a graphics card, use its video port (usually lower on the back). Using the port built into the main board is a common cause of 'no signal'. [2]
Read the power light
On Dell monitors, amber, orange or blinking white means the monitor has power but no video signal from the computer. No light means no power. [2]
Run the monitor's self-test
Samsung monitors: Menu > Picture Test. If the test fails and the screen stays blank, the monitor needs service. [1]
Try a different computer
If the monitor works with another device, the original computer is the problem. If it doesn't work with any device, the monitor needs service. [1]

Is it worth fixing?

Input, port and cable fixes cost nothing or the price of a cable, so try them first. If the monitor fails its own self-test or works with nothing, it's a monitor fault: use the warranty if you can.

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Sources

Last checked: October 21, 2026