I'm asking for a diagnose of what is probably the problem. Here goes ... laptop monitor (hp 6715s) went dark. I'm using also an external monitor with the laptop, and since it kept its picture, I'm guessing it's not the graphics card.

When the night came, and I turned on my desk lamp, I noticed that the laptop monitor is not really not showing anything, but is actually showing my desktop picture - only it's very very very dark.

You cannot see anything on it, unless the lamp is focused on it, then you can see the picture, only very dark.

Does anybody have any clue what it could be? I'm just looking for informed guessed here, so I have at least some idea of where the problem lies.

The closest repair shop is quite some distance away, so going for a bit of self-diagnose before thinking of taking it to them.