Hi shrap,
please make sure there is nothing touching the underside of the board (like a riser, bare wire, screw, etc). Sometimes completely removing the motherboard and replacing it can solve an issue like this.
another thing to make sure (even though it might sound dumb) is to make sure that your PSU is set to 115v and the switch is on. Also, plug in the 12v square p4 plug from the psu to the board if it is not already connected. This should not cause the board to fail to power on, but its a good idea to feed the board the power anyway =).
Use minimal components to test-boot the board before adding all hdd, cdrom, pci cards etc.
as DAPUNISHER said, also maybe reseat your hsf on the cpu. this NF2 board will quickly stop the boot process if there is insufficient cooling.
If none of this works, please PM me and we can work together to assure that this board will work, and if after everything it does not, rest assured that DFI will replace it without hassles.
btw, I work for DFI, and its my job to patrol these forums to make sure all issues with any DFI product can be resolved and the customer is satisfied. Thanks!
Travis H
Official DFI Support Tech