SHOW FILE EXTENSIONS

By default, Windows suppresses file extensions. This allows virus writers to make use a double extension ruse to fool users. (For this reason, any attachment with a double extension should be considered infected and the email should be deleted). To properly determine the extension of a file, make sure you have file extension viewing enabled:

In Windows 95/98/NT, open Windows Explorer and select Tools | Folder Options. Click the View tab, select "Show all files" and deselect (uncheck) "Hide file extensions for known file types".

In Windows XP, open Windows Explorer and select Tools | Folder Options. Click the View tab, select "Files and Folders" and deselect (uncheck) "Hide file extensions for known file types".

In Windows 2000, open Windows Explorer and select Tools | Folder Options. Click the View tab, select "Show hidden files and folders" and deselect (uncheck) "Hide file extensions for known file types".

In Windows Vista, open Windows Explorer and select Tools | Folder Options. Click the View tab, select the "Advanced Settings" box and deselect (uncheck) "Hide extensions for known file types."