File extensions are unique patterns of alphanumeric characters which are present at the very end of every file name. These unique patterns basically determine which program should be used to open up the file. In windows 7, by default the file extensions are not displayed. You can configure and personalize the operating system quite easily.
You can show file extensions in two ways. The first method is by using the Registry Editor and the second is via Folder Options.
Follow the step by step guide below and learn how to show file extensions in windows 7.