When it gets stuck at 3 LEDs that is an issue with RAM. I am having that issue with some Kingston HyperX.
I was originally using some 2x512 Geil Ram in slots 2 and 4, but was having stability issues and the Geil could not complete memtest without errors. When I tried the Kingston HyperX(with the shipping BIOS), it would post, but during the post there was 3 loud beeps and the RAM timings were incorrect (like it couldn't read them off the DIMMs so it set some default values). I was never able to get into Windows with this RAM in slots 2 and 4. I updated to 310 Bios and had the same issue. I moved the RAM to slots 1 and 2(single channel) but at least its working and stable now.
Anyway have you tried just a single stick of RAM to see if that corrects the issue, or two sticks in single channel mode? At least that would verify that some incompatibility with the RAM is the problem.