My laptop monitor is faulty and I am planning to use it as a 'desktop'. I bought an external led monitor. But when I connect it to my laptop via HDMI, the desktop gets extended. What I really want is to turn off the display on my laptop and use the external monitor, not dual monitor. How to do this.
Select the screen labelled laptop (or similar), select the "off" radio button and then click apply. That worked for me anyway.
There must be a key, which pressed in combination with the Fn key, will turn off your laptop monitor. That key is usually on the function keys. What is your laptop model?
Maybe you can use disper: see my answer to this question