I don't know if it applies to your mobo..!

I use the GA7VA XP, mind you I only use PC2700 RAMs at the back of my
manual it list the types of RAMs suitable for this particular mobo, I
believe that some brands will not work or become unstable.

Obviously you are using a completely different mobo and may not apply,
wonder if it's worth checking on the makes of the RAMs that are
suitable, the ones I use are Kingmax

Sounds like a ram fault, you should get the POST beep even with all
the drives and HDD disconnected, getting the POST beep indicates the
Bios has booted.

No doubt you've tried all the PCI cards are seated properly, are the
FSB clocking speeds set correctly on the mobo for the rams?

Davy