What CPU is it? How did you come across these old parts? Did you buy them used? If so, did you buy them from the same company/person and did they claim they worked together? Is just a computer you've had a while that suddenly stopped working? It's hard to help without knowing a little more background info.
We also need to know a little more about the specs. What exact RAM do you have? "1gb x 2 rams" doesn't really narrow it down at all. What 430W PSU do you have? Are those parts new or old?