I was having the same problem but I've finally got it to work. What I did was:
1. Uninstall iTunes, Apple Software Update, Apple Mobile Device Support, Bonjour and Apple Application Support (in that order).
2. Make sure that has got rid of everything to do with Apple, so look through your Program Files folders (Program Files and Program Files (x86) if applicable) and delete anything that says Apple, iTunes or iPod.
3. I also uninstalled ifunbox so I guess you should uninstall anything to do with Apple devices.
4. After you've made sure there is no trace of Apple restart your PC.
5. Download the latest iTunes, version 12 just came out and seems to work well.
Hopefully that helps some people out there, I've been pulling my hair out for nearly a month now!