Dell Inspiron 8000 POST failure- Static LED codes

Hello all,

I have a Dell Inspiron 8000 that suddenly developed a POST failure. Solid on, "Caps Lock" and "Scroll Lock" LEDs displayed for about 6 seconds then the machine powers off. I have searched all over for these old static (not blink) codes and have come up short.
Looking at the blink codes, I determined that it was most likely memory, swapped the modules around and eventually discovered that the modules were good, but the machine would not POST if there was a module in the DIMM-A slot. So, is there any other fault that can cause the above error or am is the MOBO toast and will need to be replaced?

Thanks to all,

Kevin