External monitor goes blank
 

I just installed Mint 18.2.
I use an external monitor attached to my laptop as my primary screen.
When I close the lid on the laptop, it shuts down the monitor display.
How can I stop this?

Laptops do by default go into sleep mode when the lid is closed. You should be able to disable this feature entirely from the power settings window of your distro. Different desktop environments have different locations for this settings. It would therefore be nice if you posted what environment you use :)

I have installed Linux Mint 18.2 Sonya, Cinnamon Edition.

I have power options set to:
When lid is closed - Do Nothing
Perform lid-closed action even with external monitors attached - ON

I just leave the lid open and turn off the laptop display.

Have you tried to set the option above to off?

From this link: https://forums.linuxmint.com/viewtopic.php?t=151246

To prevent suspending when running on battery power, type this command in the Terminal:
gsettings set org.gnome.settings-daemon.plugins.power lid-close-battery-action blank

To prevent suspending when running on AC power, type this command:
gsettings set org.gnome.settings-daemon.plugins.power lid-close-ac-action blank

To reverse the settings type these commands:
gsettings set org.gnome.settings-daemon.plugins.power lid-close-battery-action 'suspend'
gsettings set org.gnome.settings-daemon.plugins.power lid-close-ac-action 'suspend'

changing the power setting to OFF does not help.

I am a newbie with using the terminal. Could you be more detailed in how to enter the command line.

Problem seems solved? Perhaps power setting to OFF helped, and I just didn't wait long enough after closing lid.

Thanks all.

I'm still interested in learning how to enter terminal command properly. Is there a guide available?

There are many tutorials available on the internet for this purpose, for example this video by Joe Collins. There are also books that you can buy, like for example the Linux bible. Also: Search engines are your friend :)