The cause of the problem is: after the computer is turned on, the host running screen black screen shows no input, the motherboard bios self-test fails, the display wiring, the hardware is loose, and the display failure may occur.
1. First reconnect the monitor wiring or replace the wiring to see if it is a monitor wiring problem.
2. If the host has dual graphics cards to replace another graphics card test, it proves that it is not a graphics card problem.
3. Open the case and reinsert the memory. You can wipe the memory fingers with rubber.
4. Discharge the main board, unplug the power cord and display cable of the main board, find the button battery on the main board, and then reinstall it and turn it on after ten minutes after removing the battery.
5. If all the above methods are tried, it still won't work. It is recommended to replace other computer monitors for testing. If the monitor lights up, it means the original monitor is malfunctioning. If it also does not light, it means that there is something wrong with the host. In this case, it is recommended to repair the hardware.