It could be just that you need to re-seat the RAM. (Pull it out and pop it back in again).
From what I can see (Google Images), your motherboard has 4 RAM slots, 2 Blue, 2 Black, 4 total.
Do you have 2 RAM sticks or 4? If you only have 2, use either the 2 blue, or the 2 black RAM slots. Either combination should eliminate the problem of having 1 faulty RAM slot.