How to switch display from laptop to external monitor?

Ubuntu version is 10.10 and the laptop is Lenovo W520. A monitor is connected to the laptop through VGA. Display works under Window 7. But under Ubuntu, System->Preferences->Monitors only sees the laptop, not external monitor. How to switch and display on the external monitor? Thanks!

Solution 1:

I used to use this.. I tried it now on 12.04 with Gnome Shell 3.4 and it worked. Just connect your external monitor, place it wherever you want (top, left, right..) and in terminal run this command:

xrandr --output VGA1 --primary

I hope it is what you're looking for.

Solution 2:

Try to look for a hardware switch or function key on your laptop. The icon will usually look like a rectangle with two vertical line on the outside.

Solution 3:

I had the same problem with a (2007) Dell laptop with an Nvidia card. I already moved from the open source Nouveau drivers to nvidia-current propriety drivers for performance reasons, but Ubuntu (12.10) didn't recognize my external VGA monitor.

But after I switched to nvidia-current-updates it instantly displayed Ubuntu on my external monitor after reboot.

You can find this in Software Sources, if you have an ATI card you'll likely find something similar:

[since I have no reputation points I obviously cannot post an image!!]