Oddly, if you boot in safe mode it boots fine.
I’ve built many PC in the past and have NEVER had such problems installing an OS.
The system is as follows:
Intel D975XBX2
Intel® Core 2 Duo E6600 Conroe Processor 2.4GHz, 1066FSB, LGA775, 4MB Cache
Kingston KVR800D2N5/1G 1GB DDR2-800 PC2-6400 ECC Memory x 2
Western Digital Raptor WD740ADFD 74GB Serial ATA 10,000RPM Hard Drive w/16MB Buffer
ATI Radeon X1950 CrossFire PCI Express 512MB GDDR4 Video Card
500W power supply
IDE Plextor CD/DVD
Windows Vista installs without an issue, but I can't use it since I use AutoCAD 2007 and Solidworks which isn't Vista compat. yet. Besides, COD2 plays on XP and not Vista!

ANY help would be GREATLY appreciated!!!