broken HP Vectra VL400 DT

Hi all,

I have a broken PC, a HP Vectra VL400DT, that beeps from the moment it is
started. First it gives a long, modulated buzz sound that --- according to the
documentation --- identifies the model and type. Then it gives one long beep
that would mean the processor died, or is badly inserted in its socket.

I replaced the processor and am still getting the same beep, which is also
given when starting the PC without processor.

However, I could start the PC twice after it had been sitting half a day in a
cold car, but after 10 minutes it stopped working again. In these cases, the
boot screen initially told me that the power supply was working in protected
mode and there was a floppy drive configuration error, but I could hit F4 to
'accept' it and work for 10 minutes before the PC died again. I can not get
past the BIOS beeps when the PC is at room temperature, even not after waiting
24 hours.

So I am afraid there is a bad contact in the motherboard, that starts working
again with low temperatures or something.

I'm afraid I will have to replace the motherboard...

Below are some more details about the system:

PC: HP Vectra VL400DT
Processor: Pentium III Costa Rica 866/256/133/1.7V SL4CB
Motherboard: HP Partnumber : 411703000016R
HP SYSTEM BOARD SOCKET 370 NIC USB VIDEO SOUND 1 AGP 3 PCI

Thanks for any idea helping me to repair this thing!

Johan.