Dell Inspiron 6400,display is all black

Dear All,

I have Dell Inspiron 6400..it starts all fine...after i enter d password the screen goes black(nothing except the cursor is visible) and stays like dat...any idea wat might be wrong?the display works all fine while d bootup process...also the display works fine wen i run dell media direct which suggests dat d problem is something else...pls help


Thanks
Smriti