How to install an additional monitor when my laptop will not detect it?

Question

my asus laptop with windows 11 cannot detect an added monitor

Answer 1

I need some information about your laptop hardware and system.

1

Right click your Start Button and open Device Manager.

Expand the 'Display Adapters' section.

Please provide a screenshot of that full Device Manager window.

2

Click your Start Button, then just type msinfo and press Enter, please provide a screenshot of the resulting System Information window.

Answer 2

Use the following steps in order, stopping when the monitor is detected.

1. Confirm physical connections
   1. Turn off the laptop and monitor.
   2. Disconnect and firmly reconnect the video cable (HDMI, DisplayPort, VGA, DVI) at both ends.
   3. If possible, try a different cable.
   4. Turn the monitor on first, then the laptop.
2. Check Windows display detection
   1. Select Start > Settings > System > Display.
   2. Scroll to Multiple displays and select Detect.
   3. If using a wireless display adapter/TV, select Connect under Multiple displays instead.
   4. If the monitor appears, configure it (Extend/Duplicate) with Windows key + P.
3. Verify Windows sees more than one display
   1. In Settings > System > Display, look for multiple numbered boxes.
   2. If more than one appears, select Identify to see which is which.
   3. Arrange them by dragging the boxes to match the physical layout, then select Apply.
4. Try the Windows projection shortcut
   1. Press Windows logo key + P.
   2. Choose Extend (or Duplicate) and see if the external monitor turns on.
5. Basic hardware troubleshooting
   1. Disconnect all other accessories (docks, adapters, USB hubs, etc.).
   2. If the laptop has more than one video output, try another port.
   3. Test the monitor with a different PC to confirm the monitor works.
6. Check for Windows and driver issues
   1. Make sure Windows is up to date: Start > Settings > Windows Update > Check for updates.
   2. If the monitor previously worked and stopped after an update:
      • Press Windows logo key + Ctrl + Shift + B to reset the graphics driver.
      • If issues started after a driver update, roll back the display driver:
        1. Open Device Manager (search for it from the taskbar).
        2. Expand Display adapters.
        3. Right-click the adapter > Properties > Driver tab > Roll Back Driver (if available).
      • If roll back is not available, reinstall the display driver:
        1. In Device Manager, right-click the display adapter > Uninstall device and select Attempt to remove the driver for this device.
        2. Restart the laptop if prompted.
        3. Open Device Manager again, right-click the display adapter > Update driver > Search automatically for updated driver software.
7. Add the device manually (for some USB/Thunderbolt displays)
   1. Select Start > Settings > Bluetooth & devices > Devices.
   2. Select Add device and follow the instructions to see if Windows can add the display hardware.
8. If still not detected
   • If none of the above works and the monitor is known-good, use Feedback Hub to report the problem so it can be investigated further.

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References:

• How to use multiple monitors in Windows
• Troubleshoot external monitor connections in Windows
• Add a hardware device to a Windows device
• how to detect second monitor? - Microsoft Q&A
• Windows forces my monitor to "Disconnect this display" in the settings. - Microsoft Q&A
• How to fix compatibily between additional screen, plugged by Type "C" port" after Windows and HP update on Feb, 05th. - Microsoft Q&A
• Surface Thunderbolt 4 Dock won't use two external monitors - Microsoft Q&A
• how to update display drivers - Microsoft Q&A