1.Perhaps the computer system has started normally,but it has not been displayed.In this situation,it is necessary to check if the keyboard light is on,and then press the upper left switch case key on the keyboard.When pressing,pay attention to observing whether the keyboard indicator light is responding.If there is a response,it means that the computer system has not malfunctioned.Restart the computer once.

　　2.There is a problem with the graphics card of the host.In this situation,you need to check if the graphics card is damaged and if the host has an alarm sound.If you are using a standalone graphics card,unplug it and plug it into the integrated graphics card to check if there is a signal on the integrated graphics card.

　　3.There is a problem with the display cable.In many cases,the data cable of the display is not properly plugged in,causing the signal to not pass,the display to not light up,or the data cable to malfunction,which can cause signal transmission to fail.This situation requires plugging in the data cable properly.

　　4.The monitor is broken.You can find a different monitor and switch it to this host to see if there is a display.If there are no more monitors,you can take a laptop,connect this monitor to the laptop,and then check if it can be displayed.

　　5.Power failure.In this situation,you can check if the indicator light at the bottom right of the monitor is on.If it is not on,it indicates that it is not plugged in.Plug the power cord of the monitor into the socket,press the power button on the monitor again,and wait for the indicator light to light up.If there is a situation where the indicator light turns on and off,it means that the signal transmitted by the host has not been received by the display.Check if the VGA cable of the monitor is properly plugged in,then remove all the HDMI and USB ports at the rear,clean the dust,and then plug them back in.

　　6.Lamp tube malfunction.This situation requires replacing the light tube.It is best to take the LCD display to a professional repair shop for repair,which is safer and more reliable.