Most of the trouble caused by a damaged motherboard is as similar as to problems caused by an out of order or failing power supply. So be certain to verify if the power supply is not working or switch out another power supply to test if your problem is fixed. If it happens that you have an extra motherboard you’ll be able to solve the problem by swapping it, if that is the situation then the motherboard is most likely defective.
If the motherboard is defective check for warranty then if it is under warranty you can send it back to the manufacturer. It can be replaced by a new one. At times manufacturer might even shell out for the shipping & handling. Make it to a point that while you open a motherboard you hold all of the packaging, user’s manual, do not rip the sticker and the box itself so claiming of warranty is easy.