How do I wipe out hard drive on vista so I can reinstall os?

Little more info

Are you going back to factory settings?

Do you have recovery disks that came with computer?

Did computer come with vista?

Do you have model name and # of PC avail?

Do you want to go back to factory or just install a version of Vista you have around?

Anything else you can add will help to try and get you some working info.

Though a simple answer to your question

You do not need to format the drive. Just boot with your vista dvd. Choose advanced options from the menu that asks you where you want to install. Make sure you delete ALL partitions on the drive; then choose to install into that space. Vista will create/format during the install for you.

Note the above will destroy ALL data on the drive so make sure you backup anything important. Next I would download the full version of sp1 and apply that right after you install vista.

The above is for a retail version of vista NOT one that came pre-installed on a system.