i've just had this exact same thing happen with my 9300, and with virtually the same 22" samsung (225BW). plugged it in, went to nvidia's control panel and activated the samsung, and then it seems like it just uninstalled the laptop's lcd and now i can't get it back no matter what i try.
the laptop display is not listed in nvidia's control panel. i've removed the "default monitor" entries in device manager as well as the samsung, i've reinstalled the geforce go6800 drivers a couple times, and nothing helps. it sounds like exactly the same problem... lcd backlight comes on and i can turn it on and off with fn+f8 but there's no picture except through the samsung.
i flashed the bios with the latest from dell but it didn't help.
this just can't be coincidence... i've read about two other similar incidents on this board, and all of them happened after attaching an external monitor. what the heck could be going on here? i can't afford a new laptop right now, and can't really afford to have this "fixed", but i'm thinking there must be SOME way to figure out what's going on. any thoughts would be MOST appreciated. i need this thing working as a laptop for my business trips.