Laptop screen goes black when external monitor plugged in

[Link101]

My notebook works just fine and I was able to use my external monitor perfectly until this morning. When I booted my computer, my screen only shows on the external monitor. When I unplug the external monitor, the display goes back to the laptop screen.

I have ran many diagnostics, updated the BIOS as well the display driver to no avail. I have also completed a hard reset by unplugging and taking out power devices.

I hope someone has had this issue and found a solution.

Thanks

Simon

[Edestiny7 · Accepted solution]

Use your laptop as a second monitor

1. Right-click on the desktop and choose Properties.
2. Choose Settings.
3. You'll see a second screen. Drag it to a position similar to where your laptop screen is.
4. It should prompt you if you want to enable this monitor. Say Yes.
5. Make sure Extend my Windows desktop onto this monitor is checked.
6. Press apply.

Google search found the above, but won't let me put the link here.