But I'm not here to snipe, I have a couple of suggestions. Rather than subject
your newly reinstalled XP box to possible attack during the update process,
check out ctupdate.

www.heise.de/.../download_uk.shtml

You can use a known clean Windows computer to download the latest MS updates,
burn them to CD, and patch your XP install before ever putting it online. I use
it whenever I do a fresh Windows install.

Once your computer is fully patched and all of your major software installed,
use the Linux app "partimage" to create an image of the new, clean install.
Then, if it gets infected again, just backup files, wipe the drive and transfer
the image. The easiest way to do this is to remove the hard drive from the
Windows box, install it as a second hard drive in a Linux computer and do the
backup/restore imaging/reimaging in Linux.