Unless you chose to save it in another template, your custom toolbar will be
saved in Normal.dot. Are you being prompted to save Normal.dot when you quit
Word? Are you saying yes? If you're not being prompted, make sure that
"Prompt to save Normal template" is checked on the Save tab of Tools |
Options. If that is checked and you are still not being prompted, then
something is interfering with this process; see the last part of
http://www.gmayor.com/lose_that_adobe_acrobat_toolbar.htm for one
possibility. If you are being prompted and are saving, then the problem
could be that Normal.dot is being replaced every time you start Word (this
is not unknown on some corporate networks but would be unlikely on a
freestanding home computer).