Q: itunes fails to launch

Hello, JillHam.

Thank you for the question.  I would recommend completely uninstalling iTunes and all of it's components as outlined in the first article below.  Make sure to uninstall all programs in the order specified.  If you run into any issues with uninstalling or installing iTunes, see the second article.

Removing and reinstalling iTunes, QuickTime, and other software components for Windows Vista or Windows 7

http://support.apple.com/kb/ht1923

"The feature you are trying to use is on a network resource that is unavailable" alert when removing Apple software in Windows

http://support.apple.com/kb/TS3704

Cheers,

Jason H.