When you plug the iPhone or iPod to computer, the iTunes comes up with an alert saying:
This iPhone cannot be used because the Apple Mobile Device service is not started.
The Windows may still detects the iPhone or iPod touch as a camera device and you may explore the photos and videos content inside the iPhone. But iTunes cannot detect the iPhone, hence you cannot sync iPhone or iPod with iTunes library.
What is Apple Mobile Device service?
Apple Mobile Device service provides the interface to Apple mobile devices.
Where is Apple Mobile Device Service located in?
Apple Mobile Device Service located in “C:\Program Files\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe” (on Windows 32-bit) or “C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe” (if you have Windows 64-bit installed)
How-to Fix Apple Mobile Device service not started on iTunes?
Click Start → Run → type services.msc in the box
Or, you can simply
Click Start → type services.msc in the search box if you are using Windows Vista and Windows 7
Cannot find neither Run command box nor search box?
Click Start → Right click on My Computer → click Manage → click Services and Applications → click Services
If you have already seen Services window, find Apple Mobile Device and double click on it.
If the Startup type is Disabled, then you need to change it to be Automatic → click Apply then the Start button will be active. Click Start button to start Apple Mobile Device service, then iTunes should works by now.
If the Startup type is Automatic, but Service status says Stopped, you need to click Start button.
If you find another error message after click Start button, note the error number and find the solution of error message on senseiphone.com