I'm having the same problem that da300709 had, and I specifically purchased memory right off the list of memory for this motherboard from the manufacturer ECS website.
Memory: Kingston KHX1866C9D3K2/8GX.
I currently have the motherboard out of the can, on top of it's shipped box. Power Supply: StarTech 850W Model APE-1000X Plus(A/PFC). CPU is inserted: i5-3350P LGA1155. Power supply 6 pin connector is in ATX12 slot, 24 pin connector is in ATX1 slot Fan is on CPU, power-up with no memory...Get the 3 beeps with Post of 19, but when I add 1 stick of memory in DDR3_2 slot, where it's suppose to go, and power-up again, I go from Post 19 then to Post 55 and that's where it stays. Post 55 says "Memory not installed".
What's going on? I can't get past this Post code of 55. Someone please help!!!
Thanks for all your input. Turns out the solution: The motherboard I got did not support Ivy Bridge CPU. Therefore the post error of 55. I contacted ECS and they had me ship my motherboard back and sent me a new one that supports the Ivy Bridge CPU. They said they were in the process of pulling all their motherboards that did not support both Sand and Ivy Bridge CPU's.
Thanks again for input.