64 bit vista installation hangs end

I have got to what I think is near the end of the 64-bit install of Windows Vista. It hangs with the black screen which has the version details in silver in the bottom right hand corner of the screen.
Basically I'm using a separate physical drive to my main XP install, and I've gone through the teal screens with the Copying files, Expanding files, ...., Completing install, then a couple of automatic reboots occur then in just hangs on the black screen with the build details as mentioned above. after half an hour, the screen goes dark and the hard drive ceases all activity.
I am using :
Athlon 64 3700+ Processor MSI SLi series MS-7185 motherboard 1 GB DDR-400 RAM 2x SATA 160 GB HD