1. Locate the System Folder on your hard disk. Open the System Folder by double clicking on its icon.
2. Locate the Extensions folder inside your System Folder. Open the Extensions folder by double clicking on its icon.
3. If there is a copy of the QuickTime extension in the Extensions folder, drag it to the Trash. Note: do not empty the trash until you restart your Macintosh.
4. If there is a copy of the Apple Multimedia Tuner extension in the Extensions folder, drag it to the Trash.
5. Close the Extensions folder. Close the System Folder.
6. Drag the QuickTime icon to your hard disk's System Folder icon (not into the open folder).