Remove and reinstall all iTunes and Quicktime related components as explained here:
http://support.apple.com/kb/ht1923
1. Remove iTunes and related components from the Control Panel
Use the Control Panel to uninstall iTunes and related software components in the following order and then restart your computer:
- iTunes
- QuickTime
- Apple Software Update
- Apple Mobile Device Support
- Bonjour
- Apple Application Support (iTunes 9 or later)
Important: Uninstalling these components in a different order, or only uninstalling some of these components may have unintended affects.
2. Verify iTunes and related components are completely uninstalled
In most cases removing iTunes and its related components from the Control Panel will remove all supporting files belonging to those programs. In some rare cases those though, files may be left behind. After following the previous steps, you must confirm that the following files and folders have been removed. If any are left behind, remove them now:
If you have a 64-bit version of Windows, you will need to confirm that the following folders have been removed as well:
- C:\Program Files (x86)\Bonjour
- C:\Program Files (x86)\Common Files\Apple\
- C:\Program Files (x86)\iTunes\
- C:\Program Files (x86)\iPod\ Note: Follow the additional steps at the end of this article if you receive the alert "Cannot delete iPodService.exe: It is being used by another person or program" when trying to delete this folder.
- C:\Program Files (x86)\QuickTime\
- C:\Windows\SysWOW64\QuickTime
- C:\Windows\SysWOW64\QuickTimeVR
3. Reinstall iTunes and related components
After verifying that iTunes is completely uninstalled, restart your computer and then download and install the latest version of iTunes.