OK, I'm coming to my wits end here with this machine, never in my 15 yrs of building comps have I ever had such a hard time.
When either playing vids, or playing games, like E.T. or Advanced Warfighter it will run for a bit then pooof the comp will do a restart, no warnings nothing , no pop ups, no messages upon restart other then yahoo didn't close properly.running NFS underground 2 will result in the game just shutting off, so I'm left at it being a graphics problem.
I have swapped out every component of this PC except for the CPU, that is all that is left

My setup now is the following,

Asus P5W DH Delux
Conroe Intel Core 2 Duo 6300 1.86mhz
OCZ 1gig gold DDR2 800mhz 6400
Seagate ST3200820AS (200.0GB)
2 Radeon X1300 Pro ddr2 256 meg in crossfire setup
Cooler Master / Hyper 48, w/ 120mm fan
2 120mm cooling fans w/ Antec case,
Antec 550 watt, 120mm fan, power supply,
Windows Xp Pro media center 2005

Yes I have set up that windows doesn't restart automatically,
Like I said , all parts have been swapped out except for the CPU
other then the CPU I have almost all the parts to build a new machine, and that is frustrating, a lot of money has been sunk into this, way too much then what it is worth, it as well is not a heat issue either,
other then the Intel chipset all other parts are running well within specs

Core 0 28C
Core 1 29C
System 25C
Intel Chipset, 94C

Any help and all help is much appreciated


if you haven't already, clean the CPU cooling fins.
I'm not familiar with the OS that you are using so the help here is going to be general.
This is probably a OS issue common to the XP family. There are hidden updates/fixes that address this issue so unless you go looking for it it's unlikely to be found.
There's a setting somewhere in the XP OS that might allow you to prevent an instant shutdown at least long enough to give you a BSOD (and a memory dump written to HD), if it does, write down all the info that is provided before going further.
You might check to see if there are any drivers that need to be updated (Windows Update isn't going to notify you of all of them) specifically those that apply to your VGA adapter. Also check for BIOS upgrades.

I once had random restarts during games only.
Like you it drove me crazy for 2 weaks.
One of my 512 crucial ram sticks was riddled with errors. Changed it and it never happened again. It was this forem that recommended me get my ram checked.

RAM modules are usually quite reliable, probs. with them can look like something else.
the MS RAM check was thorough but went faster than other checkers.

You say that you've swapped out all components save for the CPU. I presume that includes the Power Supply Unit?

One thing that can cause a mysterious/random reboot is a faulty PSU that for all intents and purposes seems to run fine. A minor voltage sag or spike will force the power-good signal to go low (out of tolerance) which will result in a reset of the CPU.

But I'll bet you already knew that, eh?

If not, you can probe your power connections to assure that all line voltages are within tolerances, or simply replace the PSU.

this happens on some of my pcs but only when playing farcry or fear (intensive games). I believe the cause to be an overheating of the GPU or GRAM