I get a "File in Use" error when I know that nobody else has the document open.
This error means that the owner file (see the previous Annoyance, "Understand Document Locking") hasn't been deleted as it should have beenfor example, because Word or Windows crashed, or because the PC suffered a power outage. If the error message says the file is in use by "another user" rather than giving the user's name, the owner file has probably been corrupted.
To deal with this error, delete the owner file. The crash or outage will probably have left stray temporary files as well, so it's a good idea to clean these up, too:
Close all applications, restart Windows, and log in again.
Choose Start » Search to open a Search Results window. If Search Companion displays the "What Do You Want to Search For?" list, click "All files and folders."
~*.do? *.tmp ~*.wbkin the "All or part of the file name" text box.
Choose the appropriate location in the "Look in" drop-down listfor example, Local Hard Drives.
Click Search and give your computer a few minutes to work.
Select all the files, right-click anywhere in the selection, hold down the Shift key, and choose Delete from the shortcut menu to delete the files.
After deleting the owner file and any temporary files, try opening the document again. If Word still displays the "File in Use" dialog box, check your hard disks for errors, and then defragment them.