Stil on run the laptop,

Hello,

i have a hcl laptop , 160 gb, 2gb ram , amd 2core processer,
switch on the laptop the hard disk and mother board fan is runing but the screen not on , the screen is working normally, my friend is same adjast the chip the lap top screen will on , once on the screen laptop working narmally there are no problem, my friend adjast the chip in near hard disk ,

what the problem on laptop.
which the chip is fault, or any compound in fault.