Thanks for the reply, but I've already solved the issue and another involving BSOD upon startup of newly installed Windows 7 Ultimate x64.
Luckily I still had the old HDD with the 32bit build of Windows 7 installed. Swapped SATA leads over and proceeded to re-detect, then reformat and partition with DiskPart.
The whole ordeal can be directly blamed at NVIDIA for their wonderfully useless and OS breaking HD Audio
Drivers. Allowing them to (begrudgingly) re-install and disabling them allowed the graphics drivers to install without hanging the system.