HP 14" WXGA Glossy LED Screen Pavilion DM4-2070US

I've been brought this HP laptop and although it's switched on at the moment the screen is completely black when it would be if it wasn't for the reflection even a casual glimpse at the Machine shows that it has suffered considerable violence and damage and it would be fair to assume that the screen is broken however I've inspected it carefully and I can't see any of the usual telltale signs of cracks or blows to the side before we go rushing off to ebay to buy a new screen there's one more test that I like to do and that's to shine a light onto the screen and when we do that we can see that the screen is in fact running it's just that the backlight is out so there we can see the date and time on Friday the 6th of September okay it says it in German but hey we're all cosmopolitan where I live I guess it's time to get the thing apart and see what's going on with the backlight first thing