Understanding File Extensions in Windows

When you double-click a file to open, Windows XP examines the file name extension. If Windows XP recognizes the file name extension, Windows XP opens the file in the program that is associated with that file name extension.

But what if you want to change the program that opens when you double-click a file that has a certain file name extension? For example, a text file that has a .txt file name extension typically opens in Notepad. What if you want to open the file in Microsoft Word instead? How would you do that?

Viewing File Extensions in Windows

Depending on your settings in Folder Options, you may be unable to see the file name extensions of your files. To display the file name extensions of your files if they are not displayed, follow these steps:

1. Open My Computer or Windows Explorer
2. On the Tools menu , click Folder Options
3. Click the View tab
4. Click to clear the Hide extensions for known file types check box
   

How to change which program starts when you double-click a file

To change which program starts when you double-click a file whose file type is associated with a particular program, follow these steps:

Open My Computer or Windows Explorer, right-click a file for which you want to change the program that opens that file type, and then use either of the following methods to change which program starts.

1. Click Open With to choose the program that you want.
2. Point to Open With, and then click Choose Program to choose the program that you want.

Notice that theOpen With dialog box appears. Use one of the following methods to select the program that you want to use to open this kind of file:

1. In the Programs list, click the program that you want.
2. Click Browse, locate and then click the program that you want to use, and then click OK.
3. Click Look for the appropriate program on the Web to browse the Internet for the program that you want.
4. Click to select the Always use the selected program to open this kind of file check box if it is not already selected.
5. Click OK.

Note From now on, Windows XP will open all files that have this file name extension in the associated program. To change this, you would have to follow these steps again and associate a different program with this file name extension.

Example 1 HDManual

Example 2 Remedy Stats

Learn more at the online Microsoft KnowledgeBase