How do I get my computer to recognize a second monitor?

To detect a second monitor manually on Windows 10, use these steps:Open Settings.Click on System.Click on Display.Under the Multiple displays section, click the Detect button to connect to the external monitor.More items •Aug 23, 2021

Why wont my 2nd monitor turn on?

Check whether the second monitor is connected to a power source. Some monitors have a switch at the back to power on the display. Make sure the correct input (HDMI, DVI, etc) is selected using the built-in controls on your monitor. Connect another working monitor to check if the issue is with the graphics card.