There are a variety of possible reasons why a monitor may not display any image.
First, check the cables connecting the monitor to the computer. Check that they are securely connected at both ends and that they are undamaged. Ensure that any other cords related to the monitor such as power or audio cables are also properly plugged in. If the cables seem okay, then try changing them with new cables from another device. If this does not work, then move onto further troubleshooting steps.
Second, make sure that the monitor is powered on. Look for a power button on the monitor itself and press it if available. If there is no power button, make sure that the power cable is securely plugged into an electrical outlet and is properly connected to the monitor. You may also want to try a different electrical outlet to rule out any power issue.
Third, test the monitor on another device or computer. If the monitor is still not displaying any image then the issue is likely related to the monitor itself and not the computer. In this case, it may be best to take the monitor to a technician for further diagnosis and repair.
Fourth, check the settings on the computer. Make sure that the correct display settings are selected, such as the resolution and refresh rate. Also make sure that the display is not set to an external source like a projector. Additionally, check the display settings in the BIOS of the computer, which can be accessed by pressing a specific key (usually F2) during the boot sequence.
If none of the above steps have resolved the issue, then the next step would be to investigate the internal components of the monitor. Over time, certain parts of the monitor can become faulty and cease to function correctly. If any of the parts are found to be defective, such as the video card, power supply or backlight, then the monitor will need to be taken to a technician for repair or replacement of the parts.
Finally, there is always the possibility that the monitor is simply no longer functioning. This is usually the case when the monitor is significantly old and has been used over long periods of time. In this case, replacing the monitor will be the only solution.
In conclusion, if a monitor does not display any image then there are several possible causes. Make sure to check the cables and power, try using another device, inspect the display settings, and investigate the internal components of the monitor. If all else fails, then replacing the monitor may be the only option.