Check if there are any lights on at the front of the machine:If there are lights on the machine but not the monitor, then it’s probably a monitor issue. Check the cables that are connected to the monitor. If there are lights on the monitor but not the machine, then it’s probably a machine PC Troubleshooting issue.
With laptops, try removing the power cable and the battery. Hold down the power button for about ten seconds, and then plug the battery and power cable in again. Press the power button to see if it switches on.