Vista Ultimate 64 BSOD

Hello, i've put the finishing touches on a HTPC... with Vista 64. I'm getting a BSOD... after about 5 minutes every time. Doesn't matter what program i'm running, or if it's just doing nothing. I've run Memtest overnight, nothing there. Updated the BIOS and every single driver. Done the reinstall numerous times, put video cards in different slots, swapped the RAM, formatted hard drives, check for viruses, and sacrificed a chicken to the computer gods. I'm running the BIOS at fail safe settings, with no anti-virus software installed or firewall. I've downloaded and installed all important Vista upgrades. Not connected to the internet right now.

These are the two most recurring error messages:

IRQL_NOT_LESS_OR_EQUAL and SYSTEM_SERVICE_EXCEPTION


I've included the latest minidump files at this url...

DataFileHost - dump2.rar


CPU-Z Validator 3.0


Any help is greatly appreciated, thanks



OS: Vista Ultimate 64
CPU: Intel Core Duo E8400 3.0 GHz
MB: Gigabyte EP45-UD3P
GPU: Sapphire 100249L Radeon HD 3850 1 GB 256-bit GDDR2 PCI-e 2.0
TV Turner Card: Hauppauge WinTV HVR-1800
RAM: Corsair 4GB (2X2GB) 240-Pin DDR SDRAM 800 (PC2 6400)
Hard Drives: (2) WD Caviar Green 1 TB SATA Model: WD10EADS
Optical Drive: LG 6X Blu-Ray DVD-ROM SATA(GGC-H2OL)
Power Supply: SeaSonic OB-S12 550W ATX12v / EPS12v SLI
Case: Siverstone LC14B-MC ATX HTPC