Problem to start Vista : Reboots in loop

> Hi,
>
> I've done many research without being able to find an answer :
>
> I've downloaded the latest Beta 2 release and install a clean version on a
> new partition.
> All when smoothly, but at the end when all is done, I can't start Vista :
> The PC boot correctly, I have the Windows logo on the screen with the
> horizontal bar bellow, then black screen and the PC reboot automaticaly.
> Trying to start in safe mode don't change anything.
>
> My config is :
> Athlon X2 4400+
> Chipset nForce 4
> CGU : geForce 7900
> RAM : 1Go
>
> Any idea to help me ?
>
> Thanks in advance.
> Cyriaque