HP G42 blackscreen and when connected to monitor the graphics is broke

[Kram__]

Guys can you help me please..may laptop problem is black screen then I try to connect it in the monitor then pressing f8 it shows graphics but it's like broken monitor..please help me to fix thos or can you tell what is the problwm of my laptop..thanks in advance..

 

[webworkings]

If you can't see anything on the attached display, and you can see the desktop when you connect an external monitor, then the attached display or the cable that connects it, are the problem.

Were it something else, you wouldn't be able to see on the external monitor either.