screen black but external works perfect

i have a macbook aluminium 13.3 inch late 2008 (A1278)

my screen is black and my external mini dvi works perfectly when connected to external display. when i go to properties and look at the graphics it says no screen connected where led should be and has my external monitor under it.

i tried resetting, i tried flashing a flashlight through apple logo to see if backlight was dead and i have a new screen on order if it ever gets here.

the screen is completly black no backlight or desktop on screen and i am freaking out because it says no display connected and afraid this new screen may not fix my problem any other things that i could try??

apple care denied me because a tiny dent on bottom of the lid so i am on my own unless i can remove dent and send in again to see if they would fix if this screen does not do the job.

2.0ghz core 2 duo

2 gig ddr3 ram

nvidia 9400m

13.3 inch screen

hope you can help thanks!