System randomly powers down

[SKSmokes]

I recently bought a computer I had built for me and 2 times in 2 days it has randomly turned off. It sort of appears as a power surge--everything else I have attatched to the circuit kind of flickers but the only thing that "dies" is the new computer--everything else stays on.

Doing some quick math I can't believe I'm hitting the 15 to 20 AMP limit I have on the circuit--I have 3 computers, the other two with 250Watt power supplies, this one with a 420 watt supply, 4 monitors and 1 lamp with a 60 watt light bulb.

Even if everything is pulling maximum current, I'm still only at about 10 amps (and that's certainly not the case, both times my computers were relatively idle and I certainly don't have enough hardware connected to them to pull a full 420 amps).

It certainly could have been a brown out, but 2 in 2 days right when I bought my new computer seems like a coincidence worth asking about.

I did not build it myself but yes I'm comfortable enough poking around in there to measure voltages and what not while the computer is on. Also, the temperature gauge on the front indicates the processor is fairly cool--around 30 C both of the times this happened. I suppose I could always buy a UPS and see if it survives the brown out.....but I'm still sort of wondering if that's actually the problem. Anyone with a similar experience?

Below are the specs on the computer:
AMD Athlon 64 3800+ 939pin 90nm Venice Retail Box w/heatsink & Cooling Fan--Cooling Fans Heat Sink & Cooling Fan /AMD Athlon 64 & Opteron/
Motherboards GIGABYTE GA-K8N PRO-SLI SC939 nFORCE4 SLI Chipset DDR400 2xPCI-E x16 GBT LAN SATA Audio IEEE1394 ATX
4 x Memory 512MB HyperX DDR400MHz PC3200 KHX3200/512
Hard Drives Western Digital 250GB 7200 RPM 8MB SATA-II WD2500JS
Cases X-CRUISER-BK/420 Aspire X-Cruiser Metal Case w/ Side Window-Black
DVD ROMs SONY 16X DVD ROM IDE INT Black
DVD-RW Sony 16X DVD+RW/-RW DUAL LAYER Black Oem
Sound Cards Creative Labs Sound Blaster Audigy SE Internal PCI Card 24bit 7.1
Video Cards eVGA 256MB GeForce 6800GS PCI-Express SLI Ready N386
Operating System Microsoft Windows XP Home

 

[bill_bright]

This could be caused by many things. Heat, malware, failing RAM, failing power supply.

Does it do it as soon as you power up (when it is cool) or only after running for awhile? How many case fans do you have?

 

[SKSmokes]

It runs just fine for hours and hours--even 3D gaming. Both times it has happened it was random and not when much of anything was going on.

The case has 3 fans--one on the top, one on the side (this fan is mounted to the CPU), and one in the back. The tempterature of the CPU never exceeds 40 degrees C and is normally (when not gaming) below 30 degrees C.

 

[bill_bright]

Then I would do a complete scan for malware to make sure your system is clean. To test your RAM, download and install on to a formatted floppy Pre-Compiled MemTest86 V3.2 installable from Windows and DOS. Then, with the floppy in the drive, reboot the computer. The computer should boot to the floppy and start testing your RAM. Let it run for several passes or even overnight. You should have no reported errors.

Or, if you have 2 sticks of memory, you can pull one and run with that for a few days, then swap it with the other to see if you can eliminate one or the other.

Corrupt video drivers can cause these problems too - as you can see, these type problems are hard to isolate and fix. You might look in Event Viewer to see if there are any errors too.