Setting up Dual-Monitors on Windows

Your dual external monitors are not displaying anymore 

Solution

To get your PC to recognize multiple monitors:

• Verify that your cables are connected properly to the new monitors.
• Right-click anywhere on your desktop and select Display settings to open the Display page. Your PC should automatically detect your monitors and show your desktop. If you don't see the monitors, select Detect. Alternatively, you can navigate to the Display settings, by hitting the Windows Key and type in Display Settings. 
• Scroll down to Multiple displays, then select an option from the drop-down list to determine how your desktop will display across your screens. For the largest work area, select Extend these displays.

*Note, the first screen shot does not have an external monitor connected. 
In the second screenshot you can see both monitors. 

To change the main display, select the monitor of your choice. For this example (Monitor 1), is going to be the main display. 

You can check this box, this will automatically move your desktop icons over to the preferred monitor. 

You can also move the monitor around to fit the environment you're in. 
IN this instance my main monitor (1) is in front of you, and the (2) secondary monitor is to your right. 

Note in these screenshots that the (2) display is using a portrait mode to display. You can change these in settings by selecting the monitor, scrolling down, and selecting "Display orientation". 

If you are still experiencing issues with connecting multiple displays, ensure that device cables are connected correctly. If needed, replace the display cable or dock you are attempting to plug the cable into.