How do I make file extensions appear in Windows?

Sometimes files may appear without showing their file extensions e.g. the Word file letter.doc may appear simply as letter. It is good practice to work with file extensions showing to avoid mistaking one file for another (e.g. index.html.txt appears the same as index.html if editing in Notepad) - note that files with double extensions often pose a high virus risk.

To make file extensions always appear in Windows:

1. Open My Computer (or any folder window).
2. Choose Folder Options from the Tools menu.
3. Click on the View tab.
4. In Advanced settings untick the box beside Hide file extensions for known file types.
5. Click on Apply to all folders or Like current folder and OK to the message that appears.
6. Click on OK to close the Folder Options window.