(>'_')> Well, first check your power supply. To self check the powersupply unplug it from the motherboard and turn it on if it runs then your power supply is fine.
Then you hook it up to your motherboard. Making sure first that the CPU is plugged back in correctly turn it on again. If the power supply dont turn on or the cpu fan dont move then you might have trouble with the motherboard <('_'<)