I will deliberately omit solutions such as “the power button was not pressed” or cables inserted incorrectly.

1) Defective/insufficient video cable:

As an example, in situations where we want to use long cables (over 5 meters), we will notice that if we want to extend the connection even by a few meters that we need a cable appropriate for the situation (shielded, appropriate quality and thickness of the copper wires, etc. – all of which are properties that reflect the quality of a product, otherwise known as its ability to perform its intended function). An inadequate cable of shorter length than an adequate one (even if it uses identical connectors) will not work, but an adequate one will be able to guarantee the arrival of the signal from the system to the monitor.

2) Incorrect frequency / resolution:

For various reasons it is necessary to intervene and change the refresh rate in Hz: typical situations would be the need to use a value of or above 60,000Hz (instead of 59,994) or in rare cases 75 Hz.

3) Checking the monitor settings

Sometimes we will find the brightness and contrast settings at the value of 0 in the monitor’s menu.

4) Changing the connection type / “port”

If a monitor has problems on one type of connection (via VGA cable vs DVI vs HDMI vs DP etc) it is not mandatory that it does not work on the others. In such cases we can check all available ports / connectors; be careful that some ports are for connecting monitors in series (for “output”)(daisy-chaining) and will therefore not work.

5) Special cases: non-functionality of screen when closing the laptop lid

In Control Panel – Hardware and Sound – Power Options – System Settings we will set “When I close the lid” to “Do nothing” both on battery and when connected to the mains (power adapter connected).