I recently upgraded to Microsoft Windows 8 and found that iTunes no longer detected my iPod Touch or iPhone. Here’s how I fixed it.
1. Open Control Panel.
2. Select Hardware and Sound.
3. Select Devices and Printers.
4. Your iPhone or iPod should be displayed in the Unspecified section. Right-click it and select Properties.
5. Select the Hardware tab, then click the Properties button.
6. From the General tab, select the Change settings button.
7. Select the Driver tab, then select Update Driver.
8. Choose Browse my computer for driver software.
9. Select Browse… then navigate to C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers
10. Click Next > Close.
Your Apple device should now be detected successfully within iTunes.