Thank you for contacting the Intel Communities.
There are different things that could be happening with that port.
1. Bad port, test another port if available.
2. Bad cable, test the system with a different cable.
3. Bad port in the external display, test the system with a different monitor or different port.
4. Missing drivers, please make sure you have all drivers up to date.
5. Is the monitor recognized in the device manager? You can find this in the search bar at the start menu.
Here you can find the drivers for your device: ASUS Global
Drivers desired to be installed: -Chipset
Additionally, please make sure all the Windows updates are installed in your system.
With laptops, when you connect an additionally display, regularly there is a hotkey that would enable the second screen, in this case it would be "fn" key + F8.
How to set a second display in Windows 8.1*:
1. Invoke Windows Charms by swiping in from the right or moving the mouse cursor to one of the right-hand side corners
2. Choose Devices,
3. Select Second Screen.
4. There are four options: PC screen only, Duplicate, Extend, and Second screen only. Select the best option for you.
If yo require any further information or support, feel free to contact us back.