Rob 1

The free versions of AVG or Avast are good virus protection programs.
I would add Spybot S&D and the free Zonealarm firewall so you can monitor outbound traffic.

You want to burn those to a cd so that you can install them prior to accessing the internet once you have finished the windows install.

And I'm assuming you have service pack 2 for your windows disc. If not, you're going to want to download service pack 2 by itself. If you have that then no worries.

To wipe your drive, you should be able to just pop in the windows cd and reformat during the install process.

You will wind up at a point during the install where it will show you all the partitions that are on the disc. Just delete them all one at a time, and start over with a fresh install.

If for any reason Windows can't delete something, you can use the free version of KillDisk to just erase the drive.