Problem with Dell D620 laptop screen

[nms]

hey all,
I have a flickering laptop screen and out of focus color with my laptop screen. When it first happened i restarted my laptop and it was fine but now the problem seems to be permanent.
What might have happened to my screen. Could it be the problem with the screen or graphics card itself.. Please help me..

 

[nms]

i connected my laptop to external LCD and it worked well.. So my guess is my LCD is not working properly. Is it correct? Or is it the problem with inverter only..I want to make sure if it is with the LCD screen before buying a new one.

THanks