Computer randomly shuts down in games!!

Hey guys, Ive been trying to fix this problem for a few days now. I just built a new computer and when ever I play games it will just randomly shutdown every once in a while. Heres all the things I've already tried:

I've tried reinstalling every driver imaginable.
I've monitored the CPU temps and they never go above 50.
I've tryed different sound and graphics cards and it still happens
I've downloaded windows updates
I've run virus scans.
I've made sure nothing is shorting out in my case.
I've run every part of tuneup utilities 2006.
I've tried just about all the setting in my bios, I don't overclock.
I used the RAM, sound card, and video card in my other computer and had no problems.
I did a repair install on windows.
I ran a diognostics on my harddrive. Every things fine.

Ive tried all these things and my copmuter still just shuts down in games. the only thing I could think of is maybe somethings defective. I don't know, I'm getting really desparate. PLEASE HELP ME OUT!!!

Here are my full specs:
Amd x2 4200+
asus a8n sli
evga 7800gt
cooler master wave master.
sony dual layer dvd drive
Antec neo HE 550 power supply
pqi dual channel ddr400 RAM
74gb western digital raptor HDD
Creative X-fi sound card xtrememusic

wrong forum STUPID

No, my ram is fine, I have 2gb and I used it in my old computer and never had any problems. Would flashing my bios really help with something like this?

This may not be your problem , but i had similar symptoms a year or so ago.. it happened when i went to lan at a buddys.. my system kept resetting.. and /or shutting down.. after 40 minits of being utterly vexed, i went back to the basics.. checking wires. connections. .. and found that the Powersupply plug was loose in the socket of my PSU .. i switched cords and bam.. problem solved..

face is probably right not me but who knows

Up the DDR mem voltage to 2.7 or 2.75, and make sure the pair of modules are in approved "dual channel" slots....(some mb's are finicky with certain brands)

Using your own desired timings, or SPD/Auto for starters?

Try a single stick in an approved "single stick slot"..

Your mem working fine in one board does not mean another board will necessarily function issue free in another board, much less one with a different chipset...

Do you have the 4 pin molex power hooked up to your 7800GT?

cool, i'll try that.

Hey I just turned my ram down to ddr333 and quake 4 still eventually shut down during loading!
How could I test my power supply?

It happened to me too with a gigabyte 400 mobo and a 2400 Athlon , the cpu was overheating because the fan/heatsink were not seated properly on the cpu. Try a good thermal paste like Arctic silver. Putting an extra fan in the case might help too.

Turn off 'Automatic Restart on BSoD' in Windows for starters, so we know if it BSoDs or actually restarts the PC.

You didn't mention installing the newer nForce 4 chipset drivers at any point ?
So install them: http://www.nvidia.com/content/drivers/drivers.asp

Also run at slowest memory timings, press Ctrl+F1 at the main menu in the Gigabyte varient of the Award BIOS to get the ADVANCED CHIPSET options available. Then raise timings to the max (slowest) settings, and use SiSoft SANDRA to check what they should've been.

Also don't overclock unless you know exactly what you're doing - in case you are.

Try Prime95 (Torture Test / Blend Mode) and MemTest86+ (Ext Test) , if tests fail reduce memory timings, and keep doing it until you can get 3 passes with 0 errors.

Then consider reinstalling Windows, your registry is likely corrupt as a symptom of the faulty hardware setup.

Likely causes are (settings, faulty or compatibilty) for:
- Memory / RAM
- Video Card
- Power Supply Unit

It is unlikely to be cooling / heat related in this case IMHO.

Does the PC restart, or actually shut-down. If it shuts down then it is likely the PSU, aim for a 400+ watt PSU as a replacement if it is. A stock TruePower II (w/o EPS12V) may be a better choice for your system.

Have the same problem (see my post at http://forumz.tomshardware.com/mod [...] tdown+k8n) ...

Plz let me know if you fix the issue, and thanks every1 for the suggestions in this subject, i'll look into them...

/ Frustrated

Shutdown during gaming is almost always your power supply. Not beefy enough to give juice to your system when it's thirsty. Get something reliable.

I had a computer once with a simular problem, it was a faulty power supply, would just restart the pc with no beeps or warnings. buy a new power supply and try it out they arnt that much to buy + you said you tried and tested everything else

i think too is a psu problem.......check the amperage on the 12V rail......check the 6 pin cable on the video card ....... is your psu single rail or dual rail?

SORRY FOR THE TRIPLE POSTING GUYS....MY NET PROVIDER IS PLAYNG GAMES ON ME 8O