The operating system determines the file type by the extension of its name - this is the name of the final characters of the file name, which are located to the right of the last dot in the name. In the OS settings, the display of this part of the file name is disabled by default, therefore, to change the extension, and with it the file type, you must first enable its display in the system settings.
Instructions
Step 1
Start the "Folder Options" component of your operating system. If this system is Windows 7, then it is enough to open the main menu on the "Start" button, enter the search query "Folder Options" and click on the link with the same name in the search results. If you are using Windows Vista, select the "Control Panel" line in the menu on the "Start" button, then click on the "Appearance and Personalization" link and click on the "Folder Options" link. In Windows XP, the link to launch the Control Panel is located in the "Settings" section of the main menu on the "Start" button. After launching the panel, select the "Appearance and Themes" section, in which click on the "Folder Options" link.
Step 2
Regardless of the version of Windows you are using, go to the "View" tab and in the list of settings under the "Advanced options" heading, find the line "Hide extensions for registered file types." The checkbox of this line must be unchecked, and then the "OK" button must be pressed to fix the instruction to the system to display extensions in file names.
Step 3
Close the Control Panel and navigate to the file you want to change the extension. Select it and press f2 or right-click and select the Rename command from the pop-up context menu. Explorer will turn on the file name editing mode, highlighting the entire name. Press the End key to move the cursor to the last character and change the extension after point. Press Enter to save the change to the file extension.
Step 4
If the file whose name you are trying to change is being used by the operating system or any of the applications at this time, you will receive an error message. Close the application that is blocking the file and try again.
