Hi @aliarshad ,
What is the model number of the laptop?
Did you prove that the motherboard was the problem and not the battery or the charger or the DC-In socket of the laptop?
Are there any signs of life when you plug in and switch on the charger, i.e. any lights on the keyboard and then try to start the laptop i.e. fans starting etc?
What have you checked?
If the motherboard is proven to be faulty then the only thing to do is to replace the motherboard as this will be easier than trying to find the schematics for the motherboard and locate the problem down at the component level