Try flashing the CMOS using the jumper. I have 2 of these boards and they also don't post right at times when you kill the PSU fx.
You move the CMOS jumper from 1-2 (normal) to 2-3 (CMOS reset), boot rig, watch the blue blink next to the green, wait for it to go away, then green goes too and re-appears 10 sec later when CMOS is flashed. Then turn off computer, move CMOS jumper and boot and it posts for me.
If you have a netplug in, take it OUT. It as default has a boot order that looks for IBA something = PXE = Net boot so it scans for a boot image on a PXE compliant something. Which can take a long time for it to find out. Just plug it in when it has posted.
Has your rig posted before at all? ... If not try with 1 CPU and 1 RAM chip and replace the ram chip with the others you have till you find a good ram chip or you will have excluded the rams as the root cause.
I just hope any of this helps, have spent days myself on these boards.
No netplug. Tried resetting the CMOS with the only result being perfect LED diagnostics (no longer hanging at any point). Still no display after going 1 RAM block only during boot using 8 different ones. Could it be the GPU? (I did try with 2 different, so I have a hard time imagining that to be the case.)
Do you have a power button hooked to the board?
My own BIOS-not-moving-on problem was solved by adding a power button (either through hooking a case up, I had the board on a wooden table) or using a wire with a power button connector and button at the end from an old case.
Basically, from turned off PSU, let it boot and go policelight on the blue blinker and wait for 2 green lights and silence, then hit the power button. That did it for me.
Make sure your other 3 jumpers are set for default, especially the password one and the case intrusion one. Reset the password one.
Sorry if you know this, but once you boot the CMOS reset or the other reset jumpers, wait till the green light near the blue light, turns off and then comes back on after 10-15 sec and both greens are on perpetually. I believe it takes it that long to flash the CMOS or w/e it does.
It could be the GPU, try with the VGA port? ... Mine had a VGA port bent from shipping that almost broke it off with the serial port as well, but it still shows purple and blue (only) in the BIOS. I call it my Prince-themed BIOS
Hope any of this helps!