When I first got the parts to my new computer, I assembled it instantly. Everything went rather smoothly. I was running the athlon 64 3000+, on a chaintech nForce3 150 zenith mobo, with two sticks of 512 mb mushkin ddr 400 for memory. The computer ran fine for about a month or two, then the computer would have problems starting, the error code on the diagnostic display on the case said that it had something to do with the memory. Eventually the computer would start after restarting several times. At first, this happened rarely, about once every 3 weeks, and then it got more and more frequent until finally the computer refused to start. I have tried to rearrange the modules thinking it was something with the arrangement, no avail. I also tried using some old Kingston ram; I think it was 512 of ddr333. Same thing happened. I am going to exchange the ram and mobo for replacements from the vendor I bought them from, (I would the processor but the warranty ran out). Nevertheless, i was hoping for some insight as too the source of the problem so I can avoid it when reconstructing my computer.
Thanks all

well first step would be to run memtest to see if it is the ram..

Intermittent problem's may suggest your PSU may the real cause, do you have an alternative PSU you could try?