Screen blank after Vista install on HP dv8000 Series Laptop

Installed Vista Beta 1 Build 5112 on an HPdv8000 series laptop - no
installation errors encountered.

Appears to boot normally but just goes to a black screen that has Windows
Vista (TM) Beta 1 Evaluation copy Build 5112 in white letters at the bottom
and the mouse pointer - no icons - mouse moves but mouse buttons do not work
(ex: can't right click to get the desktop) - cant reboot with ctrl/alt/del -
have to power off.

Graphics card is an NVIDIA GeForce Go 7400 PCI Express

Processor is an Intel Centrino Duo T2300

Any ideas?

Thanks