4.1. Turn On File Extensions
You can make files easier to understand and work with by configuring Windows 7 to display file extensions.
A file extension is a code of three (or sometimes four or more) characters that appears at the end of a file name, after the period. For example, in the file name readme. txt, the "txt" part is the file extension.
Windows 7 uses file extensions to determine a document's file type. For example, a file with a txt extension is a Text Document type, whereas a file with a bmp extension is a Bitmap Image type. In Windows 7, each file type is associated with a particular application: Text Document files are associated with Notepad, Bitmap Image files are associated with Windows Photo Viewer, and so on. So file extensions ...