Microsoft Word 2010 automatically backs up your documents periodically to a special type of document called ".wbk," which stands for "Word Backup." These files can only be opened in Microsoft Word and contain a copy of a Word document that was not saved or was not the latest version. Sometimes these backup files are all you have in the event of an unexpected crash or power outage, and opening them is important to recovering your data.
Open the Start menu and type "Microsoft word" without quotation marks. Select "Microsoft Word 2010" from the "Programs" list of results.
Open the "File" menu and select the "Open" option.
Click the "Files of type" drop-down menu, then select "All Files."
Navigate to the directory of your WBK file in the "Open" dialogue, then select the file name.
Click "Open" to open your document in Word.