I have the corsair HX1000W PSU and was having the same "No Post" problem. After 3 RMA'ed Mobo's (the last one had the latest BIOS installed), 2 RMA'ed i7's, and hours of research on-line, I've learn that the auxiliary power connections are causing problems when using certain PSU's. I unplugged both the Molex and Sata auxiliary power cables and the PC starts fine. I do not know if this is some kind of a defect or if this board or PSU was designed like this for some reason. The installation manual was not exactly clear if these were required or if it would cause any issues. Perhaps it is one of those subtle compatibility issues that takes us guinie pigs to figure out??? Sure was a fustrating experience though!
Good luck with your solution.