Desktop computer won't start?

I just installed a new motherboard Gigabyte GA-P55A-UD4P and a intel I3 530 processor with Corsair Xms3 DDR3 ram. I have read the instructions 3 times and followed them to the letter and I can't get the computer to start, It will start up for a few seconds and very slowly turn the cpu fan and then shut off. I don't get any beeps and no video on the screen either. The manual says that i need a minimum of a 500 watt power supply, and that's what i'm using. Can the power supply be causing this?, it's only 8 months old and it's a Anetec Earthwatts 500watt. As far as the power connections go i installed the ATX 24 pin and 8 pin connectors and even tried a different cpu fan with no difference.