I had MANY issues with iTunes and my Windows 8.1, mostly with the syncing with the iPhone. I did this and it now works flawlessly. This is how to fix your iTunes woes within Windows 8 or 8.1:
1.) Uninstall itunes and all the other Apple Components (starting with iTunes itself, then everything else).
2.) Get the latest itunes version.
3.) Right click on the new iTunes application and click "Troubleshoot Compatibility."
4.) Run the program.
5.) Save the settings within the troubleshoot compatibility section.
6.) Finish installing as normal.
7.) Do not open the program immediately.
8.) Locate the new itunes icon on desktop, or wherever you put it.
9.) Right click "troubleshoot compatibility" on the icon.
10.) Run the program / save the settings.
Hope this helps.