Just checking, but you did plug the power cables into the Radeon HD 7970, didn't you? You could try plugging in the EZ-plug 1, but I doubt that will help. I've got a GTX 580, and I don't have it plugged in. Do you have another GPU you could test the system with, or another system you can test the Radeon HD 7970 in?
On another note, I'd be seriously disappointed if I RMA'd a board that was DOA, and didn't receive a brand new board as a result. Is it customary for ASUS to supply refurbed boards when you RMA a brand new board that has never worked? I would certainly hope not. In fact, I'd send it back to them, reminding them that you have paid for a brand new board, not a refurbished (ie. used) board, and that's what they ought supply to you.
Motherboard: RIVE (3602 bios)
CPU: Intel 3930K @4646MHz
OS Drive: 2 X Samsung 840 PRO (Raid 0)
Storage Drive: 2 X 1.5TB WD Caviar Black RAID 0, 2 X 3TB WD Caviar Red, Kingston V100 256GB SSD
Memory: 64GB G.SKILL Ripjaws Z (F3-12800CL10Q2-64GBZL)
GPU: Gigabyte GeForce GTX580 @795MHz - 1536MB GDDR5
PSU: OCZ ZX1250
Cooling: Phantek PH-TC14PE
OS: Windows 7 Ultimate x64. (EUFI)