I've revised my advice slightly, try moving on to the next step even if a component won't uninstall...
Go to Control Panel > Add or Remove Programs (Win XP) or Programs and Features (later)
Remove all of these items in the following order:
- iTunes
- Apple Software Update
- Apple Mobile Device Support (if this won't uninstall go to the next item)
- Bonjour
- Apple Application Support
Reboot, download iTunes, then reinstall, either using an account with administrative rights, or right-clicking the downloaded installer and selecting Run as Administrator.
The uninstall and reinstall process will preserve your iTunes library and settings, but ideally you would back up the library and your other important personal documents and data on a regular basis. See this user tip for a suggested technique.
Please note:
Some users may need to follow all the steps in whichever of the following support documents applies to their system. These include some additional manual file and folder deletions not mentioned above.
HT1925: Removing and Reinstalling iTunes for Windows XP
HT1923: Removing and reinstalling iTunes for Windows Vista, Windows 7, or Windows 8
Should you get the error iTunes.exe - Entry Point Not Found after the above then search the computer for copies of the file QTMovieWin.dll - you should only have one copy in the relevant folder for your system.
C:\Program Files\Common Files\Apple\Apple Application Support (32-bit Windows)
C:\Program Files (x86)\Common Files\Apple\Apple Application Support (62-bit Windows)
Delete any others and not only should this fix the problem, but prevent it from recuring on subsequent updates.
tt2