http://dban.sourceforge.net/ will thrash any drive if you want a secure delete. BE CAREFUL.
you're only in eminent danger if you have a direct internet connection (e.g. plugging your dsl/cable directly into your pc with no router). pre-sp2 windows xp still has a firewall. install it with no connections (unplug lan, etc). enable the firewall, then plug in and continue.