What is the pc100 listed for? Are you trying to mix different types of ram? Also, some socket 754 boards have a limit of 1.5 gb of ram (512 in each slot). Some boards also won't run with a stick of single sided ram mixed with a stick of double sided ram (ram with chipsets on both sides). Your board may be fine. I wouldn't touch or remove components too much. Once you get it going, I would leave it alone.
@oldie why my 2 512 mb work only on dimm1 slot? when i put them both it does not display anything with no beeps? i try to switch memory but they appear to be good both memory are working only on dimm1 slot?