I have been having a trouble on auto sync feature between my iTunes and my iPhone.
When I was searching Google, many people fixed the same problem by de-selecting "prevent iPods,iPhones, and iPads from syncing automatically" or selecting "Sync with this iPhone over Wi-Fi".
But it didn't fix my problem. One of guys claimed that he fixed the issue by clean uninstalling iTunes with registry cleaner. It didn't work for me too.
Today I fixed the problem. My problem was on Bonjour. It was installed at "C:\Program Files (x86)\Bonjour" and it didn't go away even after I uninstalled every Apple applications. It turned out that it didn't go away because one of DLL files in the folder was still in use by AirDisplay.
Deleting DLL was little tricky because Windows doesn't allow users to alter a file while it is open by any processes. Somehow there were more than AirDisplay was using the Bonjour DLL. I opened CMD window and renamed the DLL in the Bonjour folder and delete the folder. I restarted Windows7 and re-installed iTunes and AirDisplay.
Mileage will vary but this way fixed my problem and I hope this info can help others too.