The fault analysis is as follows: It is caused by the loose CPU, because the power supply of the CPU and the fan is separate. Even if the fan is rotating, the CPU may not work because of the loose CPU.It may also be that the graphics card is loose. In the above two cases, you can carefully remove the CPU or the graphics card and wipe the golden finger with an eraser, and then install it.Another case is that the two wires connecting the host computer and the display screen are in poor contact.
When trying to start the computer, press F8 to enter VGA mode. If you can enter the computer, right click on the desktop to select "Properties", enter "Settings", click "Advanced", click "Monitor", change the "Refresh Rate" to 60 or 70, and then restart
