By default all Windows operating system hide extensions for known files types. It means that all files will be named without its extension, only its names. For instance file "new.txt" is shown as "new" and in case if we need to see file extension we should enable this option. Following instructions show how to enable or disable displaing of file extension.

1. Go to "Start", "Control Panel", "Folder Option" and click on "View" tab.

2. Scroll down until you see "Hide extensions for known file types" check box.

3. Clear it if you want to show file extensions and check it if you want to hide.