Black Screen Crash

I've been troubleshooting my blackscreen crashes for over 2 months now. The monitor will go on standby, sound begins an infinite loop or shuts off completely, and I usually have to do a hard boot to get the computer up and running again. I only seemed to get them when I was playing World of Warcraft, but I recently ran PCMark05 and consistently got crashes during the second test (3D Physics) and noticed my 3DMark CPU scores were horrendous (850). So I'm thinking this is a hardware problem possibly, but I'm not sure. Here's a laundry list of things I've done:

- Scan Disk
- Defragmented the hard drive
- Run memory tests (extended suite for 11 passes with no errors found)
- Ran WoW on each individual memory stick (3 total) independently
- Cleaned out dust/debris in heatsink, fans, motherboard area, and GPU
- Installed new video card drivers
- Rolled back video card drivers to oldest drivers that support my card
- Installed new sound drivers
- Updated BIOS
- Updated chipset drivers
- Completely uninstalled and reinstalled WoW
- Ran the WoW Repair Utility
- Deleted Interface, Cache and WTF folders.
- Ran specific WTF configurations that were known to prevent crashes
- Turned off virus scanner
- Disabled all unnecessary programs
- Ran WoW with OpenGL, windowed and with no sound.
- Replaced cooling gel between CPU and heatsink.
- Ran Orthos to stress CPU (Cores stayed at about 50C)

All, by the way, to no avail. Blizzard technical support has officially stopped responding to my emails (because they can recommend nothing else) and Dell support is utterly useless.

My question is, if it is a hardware problem, what piece is causing the issues? GPU, CPU, motherboard, memory, cooling? My GPU is running about 55 C when stressed and my cores are running at about 48 C when not stressed.

Here are my system specifications:

Intel Core 2 Duo E6300 @ 1.86GHz
Bus Speed: 266 MHz
Rated FSB: 1064 MHz
Windows XP Media Center Edition SP3
Dell DXP061 Motherboard
Phoenix (11/22/07) BIOS (Dell modified v. 2.5.3)
2048 MB DDR2 Memory
Integrated Sound Blaster Audio
Geforce 9600 GT 512 MB (Forceware v. 175.19)
Western Digital WD2500JS0-75NCB3 232 GB Hard Drive

Any help would be appreciated. I'm also going to post this under the software forum.

 

I used to have the exact same symptoms and in my case it was a bad video card. Try reseating it?

 

Yeah tried reseating it already, also cleaned out the port with compressed air.