Just wanted to share my similar experience with a Dell Inspiron 6000. Very dim display (hardly seen or seen with a flashlight), sometimes would show the Dell logo at startup and then go blank. I first changed the inverter, nothing, then replaced the entire LCD assembly (Panel, inverter, and cable) from another Inspiron laptop, still nothing. Was thinking about a bad mainboard, then read about the lid-close switch and it was indeed the problem. Apparently, it was stopping the current to go to the backlight. There are a pair of white and black wires going from your mainboard (below the keyboard) to the lid lock mechanism. Not quite sure what I did, but I think I detached the one labeled main on the mainboard and while touching the other one (AUX) with this one, turned the laptop on. It worked! Then connected the wire back in its place and the problem is permanently solved (using the original LCD/inverter!)