New build crashing

[thedolphindude]

I built a new computer over christmas break this year, and I have no real issues except for one: Every once in a while, even when just on the desktop or something, the computer will power down. It's epidemic sometimes, I've had it do it 3 times in less than 10 minutes. I replaced the heat sink on the processor from stock to a thermaltake big typhoon VX, and the problems are still persisting. I can rule out the PSU because I already replaced a faulty one (a 4-pin was broken). My system is as follows:

Motherboard: XFX 750a SLI
Processor: AMD Phenom X3 8750 black edition
Video card: EVGA 8800 GS superclocked edition

tell me if you need more info.

[Darthtanion]

Ruling out hte power supply or not, it still sounds like a power issue. Either the PSU has a ground or short somewhere or the power source is experiencing some sort of fluctuation. Also keep in mind that if your power supply is not producing enough power for the system, you can also have similar symptoms.

I would not think that it is a cooling problem since these generally lead to a system lock and not a system power down.

[thedolphindude]

I just checked out the power consumption of the build, and unless my motherboard, RAM, and 2 additional PCI cards are using up a couple hundred watts (as I could not find power consumptions for these parts), then I am not over the power limit. I also checked the amperage and everything checks out. How does one test for a short or power fluctuation?

[NimrodAUS]

What is the power supply you are using. The 8800 Series cards "recomment" a minimum of i think 400watts. Just for that card. Now when you say powering down I assume you mean, it just switches off in a flash. No Lights or fans? Not shutting down? Or does it even restart? One thing you could try is running Memtest 86+ v2.11 on your ram from a bootable cd. Ive seen faulty ram switch computers off, restart em, and all sorts of crazy and nasty things. Its possible as Darth has pointed out that there is some form of short. Did you install the brass Standoff when you installed your new MB? If this issue has only just arrised than scratch that last one. But if its been doing it since new I would be looking at RAM and or PSU on the PSU front if its overloaded it will do the same thing.

[thedolphindude]

Yeah, no warning, the whole thing just shuts off. Fans & lights all just stop and I have to turn it back on. I also have another theory: I recently found out that my wireless card doesn't have 64 bit drivers, and I'm running Vista 64 bit. I was wondering if bad drivers could have something to do with it? I know they give me other issues such as outrageously slow internet, but this might be a bit far-fetched. As you can probably tell, I'm new to these things.

As far as I know, all the standoffs are in place. I'm using an Ultra LSP 700-watt PSU, and a check of all my components revealed that, to the best of my knowledge, I am not overloading it. Another question I presume is a bit noobish: how do I run memtest86+? I assume you burn the .iso to a cd, but I don't know what to do after that.

[NimrodAUS]

700Watts Should be ok. I would be trying a different Video Card to. That would be an easy test, as the 8800 also suck mega amps. To run Memtest86+ you are right burn the ISO to disk using your favorite program, Nero works, then just restart your comp with the disk in and press is it F12 to get to the boot menu and boot your DVD drive first then it will load up Automagically. So the Switching off this is for sure gunna be, A)PSU, not strong enough, dodgy or whatever. If you find my first thread you'll see that I have had two bad brand new totally different PSU's In my latest build. It can happen. B) Bad RAM. Run memtest for heap and heaps of passes. It will show any errors.
C) Power Switch. Probably unlikely. But you never know.
D) your totally Screwed, burn the whole lot and start from scratch. Jokes.

[grishkafool]

Using the Antec Calculator and making some educated guesses about your rig, I came out with a 210w system requirement. Your PSU should be capable of handling your system.

Antec Power Supply Calculator

[thedolphindude]

Okay, I put the newly burned memtest disk in the drive and rebooted. I pressed f12 I don't know how many times and did three reboots with the same method for each, but no boot menu appeared. Any other keys that might possibly bring up this menu?

[PrairieDawg]

You should be able to change boot order in the BIOS.

[thedolphindude]

To my surprise, when I checked the boot order, I saw that the DVD drive was ALREADY first! Confused, I decided that if this wasn't working, I'd try disabling the hard disk altogether in the boot list. Upon a restart, I was simply prompted to insert boot media and press any key. After checking that the memtest CD was already in the drive, I pressed enter and got the same message. Repeated about 5 times with the same result. I just used Windows to burn the disk, and made sure that I chose "mastered" under formatting options, not the live file format. Did I do something wrong in terms of burning the disk?