An installation of 2003 should offer the option to update / remove 2000, you
can however uninstall 2000 first.
NB If 2000 conatins components not included in your version of 2003 they
will not be removed in any update.
If you use OL2003, and assuming it configures itself to use the old data
file as default. In OL2003 create a new data file in unicode format & set it
as default.