1. The monitor is powered off, or the data cable of the monitor is in poor contact.
Solution: Check whether the monitor signal line and power supply connection are normal, and reconnect the monitor and graphics card line (replace a VGA line).
2, graphics card problems (unplugged or gold finger oxidation)
Solution: Remove the video card, rub the golden finger of the video card with an eraser, and then reinstall and fix it.
3, power supply problem, whether the power supply is insufficient.
Solution: To test the computer power supply, just short the green line and the black line, and ground the green line at the "PS-ON" end of the power supply (any black line). If the power supply fan rotates, there is nothing wrong with the power supply. If you don't change the computer power supply.
4, the motherboard problem
Solution: The motherboard is damaged, which cannot be repaired by individuals, and requires professional maintenance personnel to detect and repair it.
5. The monitor is broken.
Solution: Connect the monitor to another computer and try it. If it can't be used normally and the monitor is damaged, find professional maintenance personnel to check and repair it.
Note: The problem to be found is anti-static. Static electricity can easily damage integrated circuits. Therefore, before installation, it is best to touch the grounding conductor or wash your hands to release the static electricity that may be carried on your body. If possible, you can wear a wristband, which can effectively avoid static problems.