If you want to be sure that all Audition settings are removed, just exit Audition and delete all the files in (typically) C:\Documents and settings\[yourusername]\Application Data\Audition\2.0. Next time you start Audition, the settings are restored to the factory default.
If this does not solve your problem, then do an uninstall of Audition, and repeat the step above.
If you really want to re-install XP, check this information:
http://support.microsoft.com/kb/315341. Make sure you backup all your (data) files first.