Hi, I had been trouble shooting this problem for a couple of hours with no luck! I was getting "the feature you are trying to use is on a network resource that is unavailable. Enter an alternate path to a folder containing the installation package iTunes64msi" or word to that effect!
So how I fixed it 🙂
1) Head over to here and download the Windows Installer CleanUp Utility 7.2 http://www.majorgeeks.com/files/details/windows_installer_cleanup_utility.html
2) Doubleclick the msicuu2.exe file and follow the prompts to install the Windows Installer CleanUp utility. If you get the 800A0046 error message when double clicking the msicuu2.exe file, right-click on the msicuu2.exe file and select "Run as administrator".
3) If running W10 click the windows icon bottom left and start typing Install cleanup, you'll see the program you have just installed pop up!
4) Click on the program and in the list of programs that appear select any iTunes entries and click "Remove":
5) Exit the program and restart your PC, iTunes should now install without any problems 😉
Hope this helps 🙂