Not posting after 18 months of stability

So you aren't having stability issues once it boots?

Sounds more like a PSU or MB issue.

Yep. This is no reflection on you, but ignorance about PSUs is rampant. It's a piece of hardware almost as complicated as your motherboard.

Unstable voltage under load can cause any number of issues. The voltage can be unstable in various way, dropping too low, over-compensating, or just extreme voltage ripple.

For instance, a PSU might only pass it's self-check when it's cold. It has to send a power-ready signal to the motherboard before it will boot, and a bad PSU might not be able to meet it's own requirements unless it's under, say, 25C. Once it has passed it's self-test, the motherboard might be able to handle the out-of-spec voltages, or it might crash.

Or, you could have some borderline voltage setting on your RAM, so that it sometimes boots and sometimes not... but this would result in a less stable system.

Or you could have some intermittent short on the board or even a loose wire.

http://www.tomshardware.com/forum/ [...] -checklist
not a new build, but there are a few things on there, especially the bit about building outside the box.

I pulled every thing except the CPU & HSF. Most of the time I hear nothing- the HSF attempts to spin but no joy. Once I heard a continuous short beeps for 10 sec's. My mobo manual says that indicates a power error but quoted post by jsc indicates it might be a memory problem if the beeps are continuous.

Does this seem to indicate a PSU failure?

if so any recommendations on a cheap good 600w PSU?

thanks again proximon
just pulled the trigger on the 550w corsair, with the 'bill me later' & rebates it's $60. I don't think I can do better than that. It seems like a dependable unit plus it's green too.

I agree the 600w was a bit over the top but when I built the system I thought I'd be adding more HD's.

Hopefully the new PSU will solve the problem.
Thanks you again for all your help!

When a 5-pound brick gets shipped around the country, there's always a chance of something getting knocked loose. Glad it all worked out.