Vista - Vista hangs at boot 64bit - MSI P35 Diamond

I have a very wierd Vista 64 issue which I was hoping someone could help me with. When I install Vista 64 bit on a MSI P35 Diamond I have a wierd issue.

It installs fine but then after creating a profile - after finishing the install Vista reboots. Then it hangs at the Vista splash screen. It's wont boot into safe mode.

If I do a shutdown -a after creating the profile (before the first reboot) so Vista doesn't reboot it works fine. I install all the latest drivers at this point, do a windows update etc. I then reboot and it hangs as before. The system is stable, will let me install apps etc and will run perfectly until I reboot.

Interstingly Vista 64bit, Ubuntu 64bit and Windows 7 64bit hang at install. I have stripped the system down to 1 HD, 1 Gig RAM, 1 Ati 2900xt graphics card, turned off all the MB extras and it still does the same.

I have also loaded the BIOS defaults and fail safe defaults. It is not overclocked and never has been.

The only things I haven't changed is CPU and Power Supply. I have ran a memory test.

Windows XP 32bit has been running fine for the last year.

Your help would be greatly appreciated,

forgot to mention I have flashed the bois to the latest release.