For Windows Vista or Windows 7
1.Close iTunes and disconnect the iPhone, iPad, or iPod touch.
2.Click the Windows Start button .
3.In the Start Search field type Services.
4.In the Programs section of the search results, click Services.
5.Right-click on Apple Mobile Device service and click Properties in the shortcut menu.
6.Set the Startup type pop-up menu to Automatic and click OK.
For XP
1.Close iTunes and disconnect the iPhone, iPad, or iPod touch.
2.Click the Windows Start button.
3.Go to Start >> Run and then type Services.msc and press Enter
4.Right-click on Apple Mobile Device service and click Properties in the shortcut menu.
5.Set the Startup type pop-up menu to Automatic and click OK.
Note: If the above is already set to automatic, you just need to right click on the service name and then select start, so that service gets started if it is suspended for any reason.
Worked for me