Is this the 64 bit XP Pro? In this, applications that install their own hardware drivers (ie your printer) will not work until you have a 64 bit driver installed for them. You don't say what kind of printer it is, but check the manufacturer's website for a 64 bit driver to download and install. If you have no luck there, try
www.planetamd64.com good luck!
check out this forum post
http://www.planetamd64.com/index.php?showtopic=6103
apparently this is a common problem for everbody!