Windows normally defaults to hiding filename extensions for known file types. However, this can sometimes cause problems when trying to determine the real filename or when trying to rename a file since you can't see the extension. These instructions show how to disable this option.
Click on the Start button and then on My Computer.
Click the Tools menu and then select the Folder Options... menu entry.
Click on the View tab.
Uncheck the option to Hide extensions for known file types.
Click the OK button to save your settings and close the Folder Options window.
Click on the Start button and then on Computer.
Click the Organize button and then select the Folder and Search Options menu entry.
Click on the View tab.
Uncheck the option to Hide extensions for known file types.
Click the OK button to save your settings and close the Folder Options window.
