You'll need to go into your Firefox settings to change the default application for a specific file type. Click the menu button in the top-right corner of Firefox. Select "Settings" from the drop-down menu. In the Settings tab, click on the "General" panel on the left. Scroll down to the "Applications" section. Find the file type you want to change. Click on the drop-down menu next to the file type. Select the action you want Firefox to take: "Always Ask" , "Open with...", "Save File" or "Use Adobe Acrobat Reader (default)": This option will be available if you have Adobe Reader installed. [[Manage file types and download actions in Firefox|Manage file types and download actions in Firefox]]