1. The first reason why the computer host cannot be opened is that the button of the host itself has a problem, so once it is pressed, there is no response. This is the common problem of poor contact of the switch button. Therefore, sometimes you can turn on the host and decisively change the host button, or replace the connection line of the button of the On key and the Restart key.
2. The second reason is that there is a problem with the filter capacitor of the computer host power supply. When these two large capacitors burst or dew, causing a power supply problem, you can press the power on button like this, and there is no response. But sometimes the power supply of this large capacitor meets the requirements, and you can start the machine again, so you just need to replace the host power supply. You can start from the wiring board, including the wiring board, and then check whether the leads on the main board in the host are loose, and then check the start button (remove the chassis to remove the host button lead wire from the main board, which is described in the general manual, and directly use a conductor to short the start pin on the main board to see whether it can start normally), and then check the host power supply.
3. The third reason is that the memory or the golden finger of the graphics card is oxidized, resulting in poor contact between the memory and the memory slot, poor contact between the graphics card and the graphics card slot, which causes hardware incompatibility and black screen. At this time, you can cut off the power first, open the machine compartment, pull out the memory, use an eraser to wipe the part of the golden finger (that is, where there is a copper strip) back and forth for several times, use a brush to clean the video card slot, and then insert the video card again (sometimes it needs to be inserted repeatedly for many times, please be patient). If the display is lit, it means troubleshooting. If it still fails, it indicates that the graphics card or the graphics card slot is damaged. Then replace a memory slot and plug it back in. If you have a separate video card, you can also use the same method to deal with the video card, but do not change the slot.
