I have just installed Ubuntu 12.04 on an HP Laptop with Nvidia Graphics hardware. This machine used to run Ubuntu 10.10 and I have to use an external monitor as the internal screen on the laptop is broken and cannot be read. Using the LiveCD to install 12.04 and erase the previous 10.10 installation, all worked fine while installing from the live CD and the external monitor was detected and could be used. After finishing the install, and rebooting, the laptop will not recognize the external monitor and since the internal screen is unusable I cannot configure displays as one normally would. I think I may be able to alter my /etc/X11/xorg.conf file to use the external monitor instead of the default device, but I am unsure of what to change in the file. My /etc/X11/xorg.conf file looks like this:
Section "Device"
Identifier "Default Device"
Option "NoLogo" "True"
EndSection