You are on the right track - it is definitely an issue with the power subsystem.
It is very strange you could get a power control fault, since there is no power distribution board. That chassis just has a single power supply, right?
It is not likely that it is being overloaded, but you could try booting with only one processor and one DIMM, temporarily.
You're right, my chassis has a single power unit. I have only one processor and I tried to boot with only one dimm, but the result was simular. System doesn't boot, doesn't overload, CPU fans does not start spining. So I don't know what to do.
I'm sorry. I posted a message on your behalf, I can not get used to this forum.
The only other thing I can think of, is try removing all memory, and power up. See if it still gives you 1-5-4-4, or if it changes to the three beeps of "no memory".
Have you already tried clearing the CMOS by jumper?