Dell Precision 6800 Screen is no longer working

About a week ago, when I turned on my laptop the screen displayed vertical banded static.... the computer sounded like it was starting, it was just the display that was screwed up.  Now the screen is just completely white when starting up.  I have attached my computer to an external monitor via HDMI cables... and the computer starts up and runs perfectly fine.

My laptop is still under warranty, so i would like to send ity in for repairs.  Does anyone know of an address where I can send this thing?