question for system builders

[celery]

I've got a 3 year old Athlon 64 3500+ system that's recently started randomly shutting down.

The CPU is running at 27 degrees, so I don't think it's an overheating issue. I also don't think it's a software issue, as I just did a new XP install less than 6 months ago, and I keep a pretty clean OS (don't install much).

My other thoughts are it could be the memory, or the PSU. Does anyone know of any utilities I can use to isolate the problem? I don't do much gaming, and this system has worked great my work (web development) and light multimedia so I'd rather not buy a new one yet.

http://i41.tinypic.com/2qkosoo.jpg

[PapaBear]

You may also want to check the power supply.

[Reynolds]

I had one that did that once, and it was one of the components that wasn't properly seated. To avoid replacing something, I'd start with reseating the cpu, ram, expansion cards, plugs and wires etc...