My first question: What makes you think you are rid of it now? I mean, do you think your system is still currently infected?
If so, I would suggest that you allow the folks at BleepingComputer.com - Am I infected What do I do - http://www.bleepingcomputer.com/forums/f/103/am-i-infected-what-do-i-do/
to do what they can to try to help you. The personnel at that forum are much more adept at handling malware situations than we are here in the XP forum.
If you choose not to go that route and insist on reinstalling XP, then you might check out the following links for doing a clean install or a repair install.
Clean Install Procedure with Illustrative Screen Captures - http://www.theeldergeek.com/xp_home_install_-_graphic.htm
XP Clean Install, Stevens - http://www.michaelstevenstech.com/cleanxpinstall.html
How to perform a repair installation of Windows XP if Internet Explorer 7 is installed - http://support.microsoft.com/?kbid=917964
How to Perform a Windows XP Repair Install (Stevens) - http://www.michaelstevenstech.com/XPrepairinstall.htm
Edited by hamluis, 19 January 2009 - 06:16 PM.