User may uncheck this option accidentally while downloading some files previously. To re-enable the option, please follow the steps below:
For Windows XP: (Assume the file type is "ppt")
- Click "Start" -> "Program Files" -> "Windows Explorer".
- Then click "Tools" -> "Folder Options".
- Change to the "File Type" tabs.
- Scroll down to locate the file type. Highlight "PPT Microsoft PowerPoint Presentation" and click the "Advanced" button.
- Then check the option "confirm open after download".
- Click "OK to confirm.