That sounds frustrating! Let's do a full uninstall of iTunes and all related components, then reinstall. The following article explains how to do so for your operating system:
Note: It is important to remove all of the listed software, in order. Uninstalling these components in a different order, or only uninstalling some of these components may have unintended effects.
If the issue persists after completely removing, and reinstalling, please see the following article: