To change the default action for a file type:
1. Click Start, click Control Panel, click Appearance and Themes, and then click Folder Options to open the Folder Options dialog box.
2. Click the File Types tab.
3. In the File Types list, click the file extension you want to modify.
4. Click the Advanced button to open the Edit File Type dialog box.
5. Click the command that you want to make the default command, and then click Set Default.
6. Click OK, then click Close.