1. graphics card problem, (plug in the graphics card again, clean the golden finger, whether the fan is normal, update the driver, you can download the driver wizard, otherwise you need to change it for free during the warranty period)
2. connection cable problem (check the vga or dvi interface)
3. display problem (check whether the electrical outlet is powered on, if it is convenient, Connect it to other computers to see if it is normal)
It is not enough to restore it with one button. If the system CD is not prepared, the CD-ROM drive can be used. Press the del key to start the computer, set it as a CD-ROM boot in the bios, insert the system disk and restart it, which is basically done automatically by steps.