I agree with David McRitchie's response about asking in an MSWord newsgroup, but
IIRC, MSWord stores toolbar modifications in Normal.Dot.
If you close MSWord and
windows start button|search
look for Normal.dot
move it to a nice location (just in case you want to put it back).
Then restart MSWord.
But Normal.Dot stores lots of properties (default fonts, margins, even maybe
macros). You'll have to redo those changes.
(Or ask in one of those MSWord newsgroups for a real solution.)