Hi,
Note: To prevent losing the original data, please try below methods use the backup file.
Did you have backup copy of this document ?
If so, create (copy and past) a new backup file to other folder, and open document from new folder.
If it work, you can rename the doumnet to original file name.
If it still cannot work, please creat a new blank document, and copy all content from backup document to new document test if it helps.
You may also try to recover the bakcup copy of document follow the steps in this KB article:
http://support.microsoft.com/kb/316951
Best Regards.
William Zhou
TechNet Community Support
