This makes no sense.

Since i put my new computer together about 2 weeks ago it's acted strange. It's got a more-than-powerful-enough power supply, and it's sharing a 40amp circuit with only one other computer, so i know it's not power it needs, but for some reason, it'll just die... i'll start up half-life 2, start playing,and then suddenly the computer will just lose power, and i'll have to press the power button again. what's more weird, is i plugged it into an outlet at work, opened HL2:Lost Coast, went to Options --> Video, and changed the resolution. before i even clicked "ok", the computer died. this happened twice in a row. at home it doesn't do that, but it DOES still lose power for no apparent reason. i've monitored the video card, and it stays cool (usually around 52 or 53 degrees, but during 'intense' gaming it may go up to 65 or so... which is still very cool for a GTX).

I'm out of ideas. it's got to be either the video card or motherboard. i've changed power supplies with one i had laying around, but same problem. weird thing is sometimes it'll go 2 or 3 days before giving me a shutoff... other times it'll be twice in a row. i don't have my second 7800 GTX anymore, and i don't have another motherboard to 'test' either...

i'm hoping someone has some practical advice based on experience they can help me out with. Specs:

-- Opteron 148 processor
-- thermaltake 680w power supply
-- 2 GB Corsair XMS3500LL
-- ASUS A8N32-SLI motherboard
-- dual 300 GB SATA drive
-- XP Professional SP2
that should be all the info needed to troubleshoot. all updates (both for windows and games) are up to date. same with drivers for the video card, downloaded the newest from nvidia.com

processor and video card are extremely well cooled, so i know cooling's not the problem. i'm thinking it's something to do with the video card, but still... it's scaring me.

Thanks for the help in advance. I'm not a noob when it comes to computing, i've got a degree in CIS, so it's not because i forgot to "plug the PCI-E plug into the video card" or anything else obvious, but there's a massive LAN coming up in about a week in my area that i need this computer for. :(

Regards
~Lorenzo

My guess is that some unit is shorting out intermittently. Unfortunately intermittent problems are extremely difficult to isolate. If you don't have spares to swap with, you are in a real bind. You might have to take it to a shop. But if it goes days without failing, even that is not a very good idea.

Sorry, I do not check for private messages

I would do my usual "get right down to basics" thing, here. Interestingly, I JUST HAD a similar problem, which turned out to be a combination of things:

1--resoldered the power pins/connector on the motherboard

2--"Cheap"? power supply connector had poor tension on the mating power pins--gentle squeese with tiny pliers to tighten them up.

Here's what you do:

Sounds like you've already tried to eliminate the power supply--don't assume anything, and make sure.

Pull out ALL hardware, and hook up ONLY this much, and do so on a "safe" tabletop

Motherboard, cpu, and ram

Power supply, and keyboard

Video card, if separate, and monitor.

Now power up to whatever POST /bios screen you get, and gently tap and wiggle things on the motherboard. Use an insulated device, like a kitchen scraper plastic handle, or the "wrong" end of a BIC style pen.

Give a good "wiggle" to the motherboard power connector. If this gets you nowhere, hook up ONLY a floppy drive, and boot with something like a Wihnhoed98 startup disk.