Can't fix Disk Read Error, tried everything I've read

[Gladiator314]

I built a PC back in January and its been running great ever since.  Never had any hangups, freezes, or other issues with the build.  Two weeks ago my computer froze unexpectedly and upon restart I received a disk read error.  I tried several tips on the internet to fix it, and eventually the HDD stopped being detected by even the BIOS.  I bought a new HDD and reinstalled vista 64 ultimate and it's been running fine for about a week.  After receiving the disk read error again I updated my BIOS and it seemed to fix the problem for a few days.  Last night it happened again.

I've read that this could be caused by a bad HDD, issues with Vista, bad memory, or an overheating issue.  When I run SpeedFan and other temp tools, my computer runs at max at 45-50C under load.  My PSU is still cool, as are all of the components within the case.

It starts to freeze in WoW, but at random intervals.  It might be an hour, it might be 4 hours before I have any issues.  I've also had the problem when the computer was idling in vista.  I check the temperature of the system regularly while playing my games, and I doubt that is the issue.

As this is a clean HDD with a clean install of vista and runs cool, I'm beginning to think it may be a memory issue.  The following are my system components:

   Operating System: Windows Vista™ Ultimate (6.0, Build 6001) Service Pack 1
   Language: English (Regional Setting: English)
   System Manufacturer: MICRO-STAR INTERNATIONAL CO.,LTD
   System Model: MS-7388
   BIOS: Default System BIOS - updated to current version
   Processor: AMD Athlon(tm) 64 X2 Dual Core Processor 6000+ (2 CPUs), ~3.1GHz
   Memory: 4094MB RAM   - I have four 1g sticks Corsair
   Page File: 1463MB used, 6903MB available
   DirectX Version: DirectX 10
   Graphics Card:  Two HD4830 Sapphire cards in Crossfire
   HDD: 160g Seagate

All of my drivers are updated.  What is the best way to determine what memory could be bad?  Just pulling out a stick at a time?  Please lend any assistance you can, this error is driving me nuts!

Thanks!
   

[patio]

To test the HDD DLoad and run the Free diagnostics from the HDD manuf. site.

To test the RAM DLoad MemTest and create a bootable CD with the .iso...
Let it run at least 2 hours without interruption.
Any errors at all and you have a bad stick of RAM...

[Gladiator314]

Well, I've run memtest with different combinations of two of my four sticks and I've found no errors.  I did have memtest freeze once after running for about a  half hour but that was it.  What I find is odd is that when I get the disk read error with 2 sticks of RAM in, I can swap out those two sticks for my other two sticks and it'll start up fine and run for a few hours before slowing down and eventually crashing again.

Could this be a problem with the motherboard?

[patio]

To test the HDD DLoad and run the Free diagnostics from the HDD manuf. site.

We suggest this stuff for a reason....
Do this before we assume it's the MBoard.