So here is what I've found.
Memory slots 1 and 2 work with 1 ram in each slot. 3 and 4 do not work with 1 stick in each slot. 1 and 3 don't work together, 2 and 4 don't work together. 1 and 2 works together, but when i run the memory test with memory in slots 1 and 2 it fails. Each stick of memory by itself will pass. Now I am trying this suggestion . I had a similar issue one time. After running memtest to verify that the memory is good, put put two of the modules in slots one and two. Then go into the BIOS and make sure the timings and voltages are correct. For me it turned out the voltage was lower then it should of been. After I changed it I was able to successfully boot into Windows with all RAM slots occupied. Hope that helps."
What did you set your voltages at?