Unless you have an affinity towards windows XP or you want to continue using it as a work station, I might suggest switching to a Linux based OS. While I have some servers running Mandrake and SuSE, the easiest to install and administer is a free Red Hat based distro called
Clark Connect . It is very easy to use, just download the ISO and install it. Do understand though, that this will become the sole OS for the computer and that there is no GUI.
It comes with Apache, FTP, Mail, and other servers either installed or ready to be installed.