1st Gaming Rig Problems

Hi, I bought all the parts for my new gaming rig from ebuyer in march, and since then have successfully built my rig, however i have encountered many problems related to games throughout the time I have been using the rig and I am now officially out of ideas as to the cause or fix. The main problem is that I cannot play any games due to constant crashes which occur anywhere from 5 or so seconds into launching a game to about 20 minutes into playing. The main error message I receive is one stating 'The Instruction at 0x####### referenced memory at 0x#######. The memory could not be 'read' or 'The Instruction at 0x####### referenced memory at 0x#######. The memory could not be 'written'. These errors occur on games such as Team Fortress 2 and World of Warcraft. Other games simply crash to desktop with no message or warning. All other large programs I have like Reason and Guitar pro seem to run fine. The spec of the rig is as follows:

Gigabyte GA-73PVM-S2H GeForce 7100 Motherboard
Antec 900 Nine Hundred - Gaming Case
Corsair 4GB Kit (2x2GB) DDR2 800MHz/PC2-6400 XMS2 Memory Kit CL5 1.9V - Replaced once and Since changed to -
Crucial 4GB Kit (2x2GB) DDR2 800MHz/PC2-6400 Memory
BFG 9800GTX+ OC Edition 512MB Graphics card
Hi-Power Black 800W 14cm PSU
Seagate ST3500320AS 500GB Hard Drive SATA II
Samsung 40GB Hard Drive IDE
Intel Core 2 Quad Q9550 Socket 775 2.83GHz 1333
Arctic Cooling AC-FRZ-7P Freezer 7 Pro Socket 775 Processor Cooler

I am running both Vista 64 bit and XP pro, both of which show the same errors at the same time on the same games.

I have replaced the first set of RAM I ordered with the crucial memory listed above. This has made no effect on the errors. I have tried the rig without the Graphics card as well, running World or warcraft ( the only game testable at such low graphics capacity) which continues to error.
I have reinstalled most of the games, however persistent erroring across all of them, suggests incorrect installation is not the problem.
Since it has taken me so long to test all of the hardware it will be difficult at best to return all of this gear, therefore any help or fixes you can suggest would be great fully received as it will save me a large amount of time and money. I can provide any other information about the rig if it is needed. Thanks for your time in advance - Fish

If you've tried a different set of RAM, it could be the DIMM slots on your mobo. Have you tried each stick individually? Different slots?

Sounds like your motherboard isn't recognizing the memory which could lead to crashes. I would suspect bad DIMM slots on your mobo.

Well you've done a great job troubleshooting so far... You've tryed different RAM, and multiple OS's, games, and multiple installs of everything... all of which I assumed was the source of the problem until you explained you had tested them...

Unfortunately, I have to agree with drunknmunkys that it's probably a problem with your board. You might consider eliminating the HDD as the problem. It's a stretch, but it's something else to try before you go through the painful process of RMA'ing your board. Sorry for the bad news.

OK, I installed the new BIOS version 7 this morning and Team fortress 2 and World of Warcraft seem to be running fine they are at least running for much longer than they were and I have not seen any errors yet! Thank you all for your input, it has finally solved the problem which has troubled me for months! Thanks again - Fish

Is the cpu being recognized now in the device manager?