If your iPhone, iPad, or iPod touch is not recognized in iTunes on
Windows, you may need to restart the Apple Mobile Device Service. Find instructions here,
http://support.apple.com/kb/TS1567
If your iPhone, iPad, iPod touch or iPod nano (5th generation) is not recognized in iTunes on a
Mac, you might need to remove and reinstall the Apple Mobile Device Service. Find instructions here,
http://support.apple.com/kb/HT1747