wont boot

I have a custom built PC on my bench that just wont boot. Customer said there was some kind of power interruption or power surge. I believe it is running Windows 7 x64 (since 4GB RAM) but there is no product sticker and I have yet to be able to get into the OS. It has 2x4G DDR2 non-ECC memory and Core 2 Quad Q6700

Symptoms:

 -Will not boot fully into windows. Gets stuck on the windows logo.
 -Will not boot fully into safe mode (any mode) Gets stuck on the windows logo.
 -Will not boot into windows 7 CD to run diagnostics there. Gets stuck on the windows logo.
 -Will boot into Kaspersky Resecue but upon choosing a mode stuck at black screen

What I have tried:

 -Re-seating memory. Boot 1 stick, try safe mode/boot disk again.
 -Move memory to other slot, try again.
 -Remove stick, try with other stick.
 -Blowing out the dust
 -Removing the BIOS battery, all power connectors, waiting 15 min, reconnecting
 -Changing SATA ports for the hard disk and DVD drive.
 -Using an external CD/DVD drive (USB)
 -Booted up and ran MEMTEST for 3 passes. No memory errors (BOTH CHIPS INSERTED AT THIS TIME)
 -Slaved hard disk and did multiple virus scans. Nothing found.
 -Saved hard disk and ran chkdsk /r on both partitions. Nothing found.
 -Added PCI Express Video card. Tried safe mode and repair PC and it is still freezing. (Theory that onboard video may be faulty)
 -Removed PCI Express video card. Tried an alternate PSU. No change, same symptoms.
 -Removed all SATA devices, hooked up a PATA IDE HARD DRIVE AND CDROM DRIVE (Theory that SATA controller faulty) - popped in windows XP install disk - STUCK AT WINDOWS SETUP IS STARTING
 -North-bridge heat-sink too hot to the touch - removed, cleared old paste with alcohol and reapplied thermal paste. Still freezes upon start-up.
 -Tried booting into CENTOS and UBUNTU live CD. They both stall after loading screens.