the location of the profile on Windows XP will be c:\documents and settings\username
if they have a roaming profile I would suggest the following:
Rename their network based profile to username.old
delete their local profile by following this procedure:
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/sysdm_userprofile_delete.mspx?mfr=truedo the above with the user logged out completely.
Then login as the user and re-configure outlook.