Excel 2002, Chart Wizard, all of the standard and built in custom chart types
have been over-ridden with one of my user-defined chart types which has
appeared in the list as "Default". Whatever system-defined type I select I
get a mangled version of the user-defined chart called default.

On the standard types tab the option to select a default type has gone
altogether and there does not seem to be an option to delete any of the user
defined entries.

I have tried uninstalling and reinstalling Office without success. How can I
reset this part of Excel?