According to what I know about LapTops, if you decide to have an external monitos the monitor in the LapTop will turn off. I have 2 monitors in my Desktop, but I got this by getting a Video card that had a VGA and a DVI port in it, I connected both monitors and I have dual monitor (Nvidia).
On a HP you click Fn + F4 and this will turn off the monitor in you NB, and will send the signal to the external monitor. But not both.
Edited by ^MavericK!, 04 September 2007 - 07:33 PM.