It very likely may be the motherboard.
Do you know any other history behind the failure as to when the last time it ran correctly and then what happened between then and the time that it died?
( such as .... drink spilled in laptop, it took a dive down a flight of stairs, it was left turned on and put into a backpack or computer bag and overheated to death in the confined space, bad storm came thru and ever since it wont boot, child ran thru room and clotheslined the power cable to laptop and laptop dropped off coffee table to hardwood floor ..... ect ) * All these of which I have seen kill laptops.
Information as to how it may have died can point us in a direction...