External Monitor

I just hooked my new Ibook to an external monitor and I went into system propertes and display to see which resolution would look better and I hit 800x600 and then went back to the 1024x765 but when I did this my ibook screen display shrunk. Now the screen is in the very middle surrounded by black. How do I get it to go back to normal?

have you tried changing the resolution again? or go into system preferences>Displays> click the geometry tab and manually readjust it.

Nevermind, I just restarted myibook and the screen went back to normal.