dell laptop motherboard dead

hi,iv got a dell inspiron 1501 lapot wich doesnt beep or show any display at start up the power light is on and the cpu fan is spining ive try different test removing ram,hd,pci cards and replacing but no luck my gues is that theres a problem on the motherboard in the power supply area cause its giving the same symptom as a pc with dead power supply so does anybody no were i can get a full circuit or schematic diagram of the motherboard?