You can't uninstall an OS. All you can do is install a new one and telling it it has to format the drive before doing so. Should work. That makes the question much simpler: how to install Vista. The easy answer: boot from the Vista DVD and give the right answers.
Kees
I am trying to un-install Vista 64-bit and install Vista 32-bit. What is the best way to go about doing this. If there is a thread already discussing this, please point me to it. I searched and couldn't find exactly what I was looking for. Thanks in advance for all your help.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic