My initial fix would be to rename the Normal.dot and let Word recreate it…But this will remove any toolbar customizations.
Go to My Computer
Go to c: drive
drill down to C:Documents and SettingstztApplication DataMicrosoftTemplates (You may have to go to Tools|Folder Options| View Tab | Show hidden files and folders to see the Appication folder)
Rename the Normal.dot to something else.
Start Word and that should recreate the Normal.dot.