Problems with custom gaming rig

[Customer-James]

I purchased a variety of components for a gaming rig from yoyotech and put it together on Friday according to the manufacturer's specifications. I went into the store looking for some specific parts but due to supply at the time adjusted my list based on the yoyotech rep's recommendations. Although I can not confirm any compatibility issues I am worried that the power supply may not be adequate.

I can't seem to isolate the problem I'm having. The test boot went fine. It found all my components and the BIOS adjustments recommended by the component manufacturers updated appropriately. However, about 3% of the way into Windows XP installation the machine powered down. It then produced the 'error loading operating system' bit. I made a boot disk from my HD manufacturer's website and went in for the boot to write zeros onto the HD and begin a fresh install but unfortunately the system continues to power down at random times. There's not a particular point that it drops. It could be three seconds or a few minutes after powering up, but never runs for very long.
Here's the rig:

Antec P182 case (extra large case with 4 fans)
Coolmaster 700w Pro m700 power supply
abit IP35 pro motherboard
Intel Core 2 quad processor
Tuniq tower 120 heatsink
xms Corsair Twin2X2048-6400C4 RAM
500gb western digital SATA HDD
Nec ad7170 SATA DVD-RW
Asus nvidia geforce 8800gtx 768mb
Windows XP home edition.

When the thing's been running it doesn't even feel mildly warm. The 700w power supply should be more than enough.
The mobo is securely positioned. The heatsink is awkwardly sized, heavy and doesn't look very securely placed but I have been assured that this is normal and it appears to be working. I was meticulous in assembling all of this and tripple-checked everything but that doesn't mean I didn't make a mistake. Clearly if the machine is powering down at random moments something's wrong. Any advice at all would be welcome because I'm getting desperate.

Regards,
James

[YOYOtech - Courtney]

Hi James,

Can you please make sure that the CPU cooler is securely fastened and that you have used enough thermal paste. The problems that you have described usually arise when the CPU is overheating.

[cheesyboofs]

it doesn't even feel mildly warm.

Is a very good indication of the fact that maybe the CPU doesn't have enough contact with the heatsink. If you quickly go into the BIOS before it turns off what temp does the CPU read?

Regards

[gremlin896]

Yea, I had a problem like this. I just reapplied some thermal paste and it worked.

(Bang and the heat is gone)