|Try to install Vista like it is full DVD rather than upgrade DVD and see if this resolves the install issue.|
After booting to the Vista DVD, choose Advanced... rather than Upgrade initially and continue installation that way. Uncheck Automatically Activate when I am online checkbox and do not write in the Product Key.
This will install Vista as a 30-day evaluation version.
If Vista installs this way, then that means you have no hardware-wise or software-wise problem in your system.