Here is what Microsoft has to say on the subject in Article ID 313472 (formerly Q313472). I have used this with Word 2003, but I have no idea if it works for previous versions.
1. Quit all instances of Word. To do so, follow these steps: a. Save all your work, and then quit all programs.
b. Press CTRL+ALT+DELETE to open the Windows Security dialog box.
c. Click Task Manager, and then click the Processes tab.
d. Click Winword.exe, and then click End Process.
e. In the Task Manager Warning dialog box, click Yes.
If you receive a message that states that the program is not responding, click End Now.
f. Repeat steps d and e for each occurrence of Winword.exe.
g. On the File menu, click Exit Task Manager.
2. Start Windows Explorer, and then browse to the folder that contains the document file that you tried to open when you received the error message.
3. Delete the owner file.
The owner file is located in the same folder as the document that you tried to open. The owner file name uses the following convention: It begins with a tilde (~), followed by a dollar sign ($), followed by the remainder of the document file name. The file name extension is .doc. For example, the owner file for Document.doc is named ~$cument.doc.
4. Start Word. If Word asks you whether you want to load the changes that were made to the Global or Normal template, click No.
5. Open your document.
