Will48: That's happened to me when the memory is not configure manually. If I leave it at AUTO my board does that.
Mathew: I had the same issue after I was trying to configure my 1600Mhz memory to run at 1600Mhz. CyberPowerPC sold me this Corsair memory (CM3X2G1600C9NX) that supposedly runs at 1600Mhz but I can only get it to run sort of stable at 1066.
Try removing all SIMMS and insert just one. Then power on. It may not come on. Then power off. Insert a second SIMM. It should come on.