hello ,
i had the same problem , the screen is black but when I plug another screen by VGA it works ,
and the web cam works .
after 3 days searching and checking i found the problem and fixed it .
the problem is '' the video cable '' that connect the screen with the motherboard . because the screen closes and open many times , that causes the same cables are broken or corrupted .
the solution is to buy a new video cable ( before you buy, you have to specify the exact referance of the video cable ).
or , it is what i did ,
to fix the cable or cables that are broken by connecting them .
i did it it works correctly like it never happen. :)