One of my clients called me this week with an emergency. They couldn’t get one of their computers to respond when they turned it on Monday. They shut it down Friday because they weren’t going to be in the office over the weekend. The two monitors never came on with the Windows 10 desktop when the power button was pressed. Over the phone, I had them unplug the power cable for a minute and then back in. This didn’t help so I had them try a different electrical outlet for the computer and this failed to help as well.
I made an on-site service call and proceeded to check out the situation. When the computer button was pressed, it looked like the computer was dead. Nothing was on the monitors and the computer was quiet. I listened closer to the computer while looking at the back and could see the fans turning and the air flow could be felt. The computer WAS on and the problem was the monitors. The monitor connectors were disconnected from the video connectors on the computer and reconnected. Eventually they came alive. The setup was working now, I I never could explain what happened or why the monitors recognized the computer sporadically.