If you have trouble uninstalling iTunes you might want to visit this website: http://HowToUninstalliTunes.com
iTunes can be very difficult to uninstall properly because of a number of
registry keys left behind by other pieces of software that it works with.
The article explains what you have to do step by step if you can`t uninstall iTunes using ADD/REMOVE programs.
If you don`t completely uninstall it properly you will get all sorts of errors when trying to install a new copy...
even if you try to write over your existing copy.
This download saved me hours of aggravation and I did not lose my music!