iTunes for Windows: “iTunes was not installed properly. Please reinstall iTunes” message

When opening iTunes for Windows, you may see the following alert:  "iTunes was not installed properly. Please re-install iTunes. (Error 7)." When opening QuickTime for Windows, you may also see the following alert: "QuickTime failed to launch because it is not configured correctly; reinstalling may correct this problem."
  • iPod nano (5th generation): Error message saying that iPod ‘could not be identified properly’
  • iPhone, iPad, or iPod is not recognized properly by computer when USB drivers are not installed properly or are out of date
  • iPhone or iPod touch: Error message when connecting device to iTunes on Windows computer
  • iTunes: How to remove and reinstall the Apple Mobile Device Service on Mac OS X
  • How to find which version of Windows XP is installed on your Windows PC
  • What to do when you cannot install VoiceOver Kit on Windows XP
  • iPod: What to do if Windows displays an “itunes.exe – Corrupt File” message
  • iTunes for Windows: Doesn’t open after upgrading in Windows Vista or Windows 7
  • iTunes for Windows: Doesn’t open after upgrading in Windows Vista or Windows 7
  • Upgrade notification message when opening an iWork document