Whenever you try to open a file, the Windows Operating System checks the extension at the end of the file to determine what program should be used to open it. Normally, this process works without anything needing to be done on the user’s end. For instance, if you click on a .jpeg file in Windows it might open using Windows Photo Gallery. But if you install Photoshop, you might suddenly realize all of your images are now opening with that program. To fix this, you will need to change the file association. The concept for doing this is the same in every version of Windows, but the process of changing it may be different from Windows XP to Windows 7.
Change What Program Opens a File
To change a the program a file opens with, right-click the file and then choose “Open With.” You will then see a list of popular programs installed on your computer. You can select one of those or click “Choose Program,” which will give you even more options. Be careful what you select, as you would not want a Word document to be opened by a graphics editor.
To view file extensions on each file, go to My Computer and select Tools, then Folder Options. Select the View tab and in the Advanced Settings area uncheck the option to hide extensions for known file types. You should now see an extension on the end of your file names.
If you’re running Windows 7, you can change file association in the control panel by selecting the Default Programs icon. You will see a list of programs and have the ability to change what program opens them.
The key to keeping your program file association in order is to be careful when installing new software. New programs will try and take control of as many formats file formats as possible. For example, Quicktime will try and take over every type of movie and sound file it possible can. Be careful when installing a new program, as it will often give you a change to uncheck boxes and set preferences before it installs. If it does not, you will need to perform the measures mentioned above to correct the association.