By default, the Windows operating system displays only the file names along with the icons
of the associated application
which is used to open the file. For the files that the Windows operating system does not recognize, the full filename including the extension
is shown. The Windows operating system provides users with the choice to change the selected program to open a particular type of file
. It will show a list of recommended programs and other related applications installed on the system for the user to choose from. Users can also associate an application to a file extension
Display all file extensions
Windows XP by default will mask Extensions of known type. To view all extensions, from My Computer or Windows Explorer, click the Tools
menu and choose Folder Options
, then click on View
Turn off the box Hide extensions for known file types
Modify an existing file association
If a file extension is already assigned to a program it is possible to change the association
Follow the steps below:
Right-click on a file with the extension whose association must be changed, then click Open With
In the dialog box opened, choose the program with which the extension must be open (or Browse to select a program of your choice).
Check the option Always use the selected program to open this kind of file
and then confirm by clicking on OK
Create a new file association
If the extension is unknown to Windows, it is possible to create a new file association.
Right-click on a file.
Click on Open
, or double-click the file.
Windows XP displays a dialog box informing no program is associated with this file. The dialog box open and offers the following two options:
Use the Web service to find the appropriate program.
Select the program from the list.
Choosing the second option. In the dialog that opens, select a program or click Browse to navigate until you find the program corresponding to the extension.
Check the option Always use the selected program to open this kind of file and then confirm.
The file will now be associated with a program.
Manage the list of file extensions
From your Windows Explorer, it is possible to modify, create, delete, change the icon associated with the type of files, or restore the type of files by default.
Click on Tools
and then Folder Options
Select the File Types
The list of extensions, the type of files as well as the program associated to them will be displayed.
Select the one you want to modify.
If you are using Vista, you can follow the same steps!