My tool bar no longer displays the Bold, Underline, Center, Right or Left
Justify icons. How do I reestablish the full tool bar?
Open the Tools > Customize dialog.
If you want the toolbar to be exactly like it was when you first
installed Word, click on the Toolbars tab, click once on Formatting,
and click the Reset button.
If you have other customizations on the toolbar that you want to keep,
add back the missing buttons: Click on the Commands tab, click the
Format category, and drag each of the missing buttons from the
Commands list to the toolbar. You may need to right-click each button
and select Default Style from the resulting menu to remove the text
from the button and leave just the icon.
See
http://www.word.mvps.org/FAQs/Customization/AsgnCmdOrMacroToToolbar.htm
and
http://www.word.mvps.org/FAQs/Customization/RestoreMenuCmd.htm for
some more information.