Search for the file normal.dot
If you are running XP this will be a hidden file.
Click Start, click Search, click All files and folders, and then click More advanced options.
Click to select the Search hidden files and folders check boxes.
In the search results, right click normal.dot, select Rename and call it something else e.g. abnormal.dot
Start Word and see if the problem is fixed. If not, which version of Word are you using?