Display Problem

I have a Dell Studio 1558 laptop.
The display was working fine till some time back before shutting down when i was trying to startup the computer the display is not coming. The power button lights up on switching it on and you can hear the fan sound,
there is no any beep but there's no display.
if i push the power button for turning off it is goes immediatly off within second .Is the problem with the LED screen or might there be a connection problem? Please help!!

Now i found that my LED screen havng no problem. when i press D whille starting up it shows colour pattern.
what will other possibilities ?