Shutting down by itself

[cerv]

Hello.

I've been upgrading my old PC after accidentally frying my old motherboard. It's turned into almost a new build:
New PSU, 450W
New motherboard (clearly), ECS 865PE-A7
New Processor (Intel P4, 3.4)
Old graphics card (apparently a 256 GeForce - obviously not a very good one)
Old sound card, Sound blaster Audigy
Old TV card
Old (although actually quite new) Microsoft keyboard

There's more, like an old hard disk, two old CD drives, floppy etc., but none of this is causing the problem (since I have removed them).

Now, the problem is that it seems to have taken it upon itself to turn itself off after circa 5 minutes (of activity or not) with the above mentioned items installed. Anybody have any idea as to why?

At first I thought it might be a safeguard for the Processor (as I don't think I did the thermal contact too well), but stripped down to the bones (i.e. motherboard, processor, power only), it didn't turn itself off, (and the temperature shutdown on the BIOS is disabled).

Now I've removed the keyboard, it doesn't seem to be turning off either, although I can't see why a keyboard would make it turn itself off. My only thought is that the lack of keyboard is halting the BIOS from doing all that stuff it does. After having tried it with and without a keyboard a number of times, there certainly seems to be a correlation! What could be the problem though?

Any help would be greatly appreciated, thanks!

[ski]

If the CPU came with a thermal pad, then did you remove the plastic protective cover from the pad?
If you did, then did you install the CPU without applying thermal compound?
If the CPU did not have a thermal pad, then did you apply just a small of compound to both the CPU die and the heatsink?

Recommend that you do not disable the temperature shutdown safety feature in BIOS. Doing so can burn up the CPU.
What are the temperatures in BIOS?
Is the temperature shutdown option disabled when the KB is disconnected?

[cerv]

Thanks for the reply. I see that you think it's the processor overheating which is causing the problem - I completely agree.

In answer to your questions: yes, it came with a thermal pad, but I had to remove it, and I applied thermal compound. The temperature shutdown option has always (always, as in I never touched it) been disabled in the BIOS. The BIOS told me the temperature was a fairly stable 68C, which is pretty hot, but not enough to kill the processor (yet, anyway).

I didn't really want to have to re-do the contact between processor and heatsink again, but I did. I think the problem the first time lay in my not wanting to break the motherboard (as this is my third!), in so doing I don't think I attached the heatsink onto the motherboard firmly enough. This time I put more stress on it, and the BIOS now tells me a fairly stable 43C, which is far better! That is, so far, so good.

My theory is that the keyboard halt warning stopped the BIOS from loading to the point where it would shut itself down from the processor being too hot. Still wonder why it was turning off with the option being complete disabled anyway!

Anyway, it's been running for a while now and still going...and I've turned the temperature shutdown on now. Thanks.

[ski]

You're welcome.
The CPU's temperature was probably a lot higher than 68 C as the MB's temperature sensor may not have been in full contact with the bottom of the CPU die if the heatsink was not properly secured initially. This means that the Pentium 4's built in thermal trip logic shut down the system, even if the BIOS overheat option was disabled.
Anyway, I'm glad that you were able to solve the problem, and things are now running smoothly.