Question : Problem: Random Reboots.

I recently built a new PC around a Koolance water-cooled case.

For a over a month now it has been running fine, however now all of a sudden it has started to reboot at random for no apparent reason, I can be using it for 4 hours and it will restart or it could be 10 minutes.

Here is the spec of PC:

      Intel P4 3.4
      ASUS P5AD2 Premium
      ASUS X800 PCIe
      PC Power and Cooling Turbo Cool 510
      1 x 1 gig stick of crucial PC 4200 DDR2 RAM
      2 36gig raptors drive configured on Intel RAID 0
      XP Pro

As I mentioned before the system is water cooled, that includes the CPU, graphics chip and hdd.

At first I though the culprit was something overheating was causing the system reboot, however the system does always reboot under heavy loads, just before it rebooted yesterday the CPU was at 28c and the motherboard was at 45c.

Last night however I though I had cracked it as I removing an external hdd I recently added.  The reason for this is that this hdd required an external power supply and at the moment I have one wall socket with a six way extension bar coming out of it all of which I utilised by various computer products. My reasoning behind this was perhaps the demand for power was out stripping supply.

I then left it on over night but alas it still rebooted.

The only other problem I’ve been getting it is that if the USB card reader is plugged in the system will sometimes not boot fully, not sure if this is related or not.

I’m really looking for any tests that I can do which will prove that a component is faulty, as stripping this system down when it’s full of water is no easy task.

Oh yes, all overclocking has been removed, the system is running as 'standard'

Answer : Problem: Random Reboots.

You can start with testing your RAm, or swapping it, or running with 1 stick at a time
Test :   http://www.memtest.org/

for the rest, you can go 2 ways to diagnose : hard or soft
Soft : disable everything at startup in msconfig : start>run, type msconfig + enter
select the startup tab, click disable all
select the services tab, click hide microsoft services, clik disable all
reboot, and add on till you have the culprit

Hard : disconnect or disable everything not neede for troubleshooting, so start with a minimum: 1ram stick, kbd+ mouse, video card, 1 harddisk
if the provblem is gone, you can add on devices till you find the bad guy

i suppose the interior of your system is dust free, but check if all fans are running, and try with another power supply