You can replace the power supply and you can replace your motherboard. There is not a part of the motherboard that can be removed to just replace it. Its one whole piece. Will your computer still boot up and work fine, but just not charge? Or will it not charge or turn on at all?
ok well thats actually good to hear. Now its really impossible to say if it is the charger or the motherboard that is the problem, but the charger is the cheapest and easiest to try and see if it is defective. You will either need to find someone with the same laptop as you, and try theirs, or purchase one from a store or off of ebay. If this doesnt work, your motherboard will need replacement.