So I was testing my laptop on my external scree and managed to cycle through the modes until I hit the one which displayed only on the external monitor.
This just output a green screen and nothing else. Now, whenever I connect the laptop I can't use the fn+f3 button to swap between screen modes. It appears that it's stuck on this output.
Also to make things worse, the laptop seems to remember the setting, so now whenever I plugin the display all I ever get is a green screen. I've tried rebooting the laptop, but I think the only way now is to reset the laptop somehow so it doesn't know that it's been connected to the external screen and I can use 'span' or 'mirror' mode instead of 'external only' mode, which clearly doesn't work.
Update
I've tried swapping to terminal using CTRL+ALT+F1 but the external display goes to sleep.
I've tried using microDisplayPort -> HDMI -> DVI to the monitor with the same outcome.
It works fine on my TV using HDMI, but I haven't tried cycling the modes.
I got it working on the TV, and then moved the laptop to the monitor hoping it would work, but I had the same outcome.
I believe there is a setting somewhere in the system which is remembering the last used configuration for the specific monitor, and I would like to reset that, so that I can at least use my screen in span mode.
Best Answer
Clearly you can't see what's happening on screen when this is the case, right? If so, this is a bit of a long shot, but try punching in CTRL+ALT+F1, then type in your username, enter, your password, enter, and then try
Maybe that'll work. If not, your display probably isn't called LVDS1, in which case, disconnect from the external display and do:
then replace 'LVDS1' above with whatever that command says your display is. It'll give you something along the lines of:
in which case, 'LVDS' is what you should use instead of 'LVDS1'. Hope that helps.