D850GB Memory Issues

I have an Intel D850GB motherboard with a 1.4GHz P4 and 128MB RAM. The
BIOS recognizes the RAM size, but when the computer boots, the memory
check only reaches 28MB and it'll give 4 beeps and attempts to boot.
The memory are in two 64MB modules. Can someone suggest how to isolate
the problem without having to go out and buy new RAM modules? I can't
test with just one because the motherboard won't even attempt to boot
without two modules. Is it possible that the problem is on the
motherboard or non-hardware related?

Thanks in advance.