Vista Business-Clean Install-Hangs after First (1st) ReBoot during 'Completing Installation' HELP!!!!

Am trying to install Vista Business to my laptop:
Dell Inspiron 8200
1 gig RAM
100 GB hard drive
ATI Radeon Mobility 9000 video card w/64 megs RAM

The upgrade advisor tells me everything should work, but that I won't be
able to run Aero.

Doing a clean install, the first part completes -- the system reboots after
'Installing Updates' -- after the reboot, 'Completing Installation' runs for
a minute or so, then the system hangs. Keyboard is locked, hard drive
activity stops and the only way out of it is to hold the power button until
the device shuts off. Powering back on brings up an error that the
installation was terminated and needs to be started over. Have tried about
10 times so far, same thing. Reading through the posts here I found
reference to removing the DVD before the reboot, which I tried but this
didn't help.

Microsoft support says to contact Dell, Dell support says to contact
Microsoft Has anyone run into this? From what I've been able to find in
this newsgroup, the video drivers are being installed after the first reboot
(I think)...? Am at a loss as to what, if anything, to try next -- any help
would be >>>much<<< appreciated!!!! Thanks!!!!