My LCD panel has gone blank! The laptop boots up fine, but the panel is blank

My Fujitsu Amilo M3438G LCD panel has gone blank! The laptop boots up fine, but the panel is blank. Upon close inspection, I can just about see the Windows XP login screen, although this is extremely faint. All is fine on an external monitor. I have noticed that pressing the Fn+F4 key combination to switch to an external monitor lights up the LCD for a fraction of a second. I assume this is a problem with the backlight not triggering when it is supposed to. I have taken the back off it but there is nothing obviously loose.
This has happened a few times in the past, but upon powering off then back on it has always sorted itself out. Oddly enough, in the past, it only seemed to happen when the power cable was connected but not turned on at the mains, although this could be a coincidence.
I have had this laptop for about 8 months (and so out of its 6-month warranty) and it stays at home, i.e. it does not travel!
I assume that the backlight itself is ok, since every time I press the Fn+F4 key combination it lights up, although briefly. As suggested here, I guessed it may be the ‘close-lid switch’ which has somehow got stuck in the closed position; however, I cannot find such a switch.
Just a quick update, I have now managed to take the LCD panel apart. I notice there are thin wires running vertically along the left and right sides of the panel (grey on the left, black on the right), connected to some small strips of metal. I wonder if this laptop uses a magnetic field to determine whether the lid has been closed as I cannot see a switch.
Could there be a problem here?

First of all I would like to mention two wires connected to small strips of metal you found inside the LCD panel. Most likely they are wireless card antennas and they have nothing to do with the backlight.
If you take a look at the generic notebook display assembly diagram, you’ll see that there are four parts that can cause the backlight failure: lid close switch, video cable, FL inverter board, CCFL (backlight bulb) itself. Let’s go through them one by one.
The video cable conducts data signal from the motherboard (video card) to the LCD screen and also provides power for the FL inverter board. I don’t think that you have a bad video cable because you still can see a faint image on the LCD screen and the backlight lights up for a second when you use Fn+F4 keys, so the power is coming to the FL inverter board.
I don’t think it’s the lid close switch issue because the backlight flashes sometimes. If it would be a stuck lid close switch, the backlight wouldn’t flash when you press Fn+F4.
Most likely it’s just a bad FL inverter board and you’ll fix the backlight issue if you replace the inverter. I guess it also could be a failed backlight bulb, but I would go with the inverter replacement first.
Here’s my suggestion. Open up the LCD panel again and reseat cables on both sides of the FL inverter board and the backlight still will not light up, replace the FL inverter board. Most likely that’s your problem.
Let me know how it goes.