What should I do if the old man-machine suddenly turns black and can't turn on the machine?

A * * * has the following four situations, as follows:

1, the software conflicts with the system, and some software may have some loopholes or damages, resulting in a direct black screen during use;

2. The mobile phone is dead. If the battery is completely exhausted, the screen will be black and the machine will not start. At this time, you need to charge;

3, motherboard or screen hardware problems, whether there has been a recent fall, touch phenomenon, the phone's motherboard or screen is damaged, so it can not be displayed normally, at this time may still be working, but can not see the screen;

4. For the above situation, we can buckle the battery and restart it. Apple phones can press the power button and the home button at the same time, thus forcing them to enter bios mode, or linking computers for troubleshooting. If it can't be solved, go to after-sales maintenance.