How to Turn On Extensions for Known Types (Windows)

• Reveal file extensions for known file types.
• This is a feature bug in Windows where Microsoft does not display the [usually 3-character]  extension of a file. This has been used in the double-extension exploit:
• Excerpt: A way to trick users into opening a virus. Many people have learned that text files (.TXT) and image files (.GIF, .JPG, etc.) are safe to launch because they are data and not executable software. They have learned to be leery of .EXE, .VBS and other extensions that are executed immediately. Thus, virus writers try to trick more people using double extensions, so "I LOVE YOU.TXT.vbs" is really not a .TXT file, but a .vbs file, a Visual Basic Script that is executed immediately
• Open Windows Explorer [Win]+[E]:
• Press [Alt] to make the menus appear
• Tools --> Folder Options..
• Go to the View tab
• Check "Always show menus"
• Uncheck "Hide extentions for known types"