Generally mobos dont fail from new, i know there is a random selection of a given N samples to fail but still a lot of the time its human error. (dont worry its happened to me hehe)
Usually once youve connected the CPU, RAM, PCI express HD and Power supply, there are sometimes little LED lights on the motherboard to say that power is going through. I cant say they are on every one. Can you see any of them? Are any of the fans going around? No noises? Nothing?
The Cmos idea is good but dependent on how old it is, used to be switching a jumper from say pins 12 and putting them in pins 34 and then switching back again. Thats a common cause of no life in computers. See CMOS on the mobo instructions.
Just check to see if everything is fitted properly, CPU etc. Also make sure your power supply is properly connected.
its difficult to say without seeing it.
Hope you get this sorted mate, i know how frustrating it can be