Your on windows, right? Try this:
Verify iPhone Driver/Service Installation:
iPhone requires two important pieces of software to operate properly on Windows. First, the driver must be installed; for iPhone the driver is USBAAPL.SYS. Second, Apple Mobile Device Support must be installed as a Windows Service. If these are not installed, see the Reinstall iTunes section below.
Verify that the driver is installed by connecting iPhone to the computer and following these steps:
1. On the Start menu, click Run.
2. In the Open field, type devmgmt.msc and click OK. A list of devices will be displayed.
3. Scroll down to Universal Serial Bus controllers and click the small plus sign to expand this group. iPhone will be listed as either Apple iPhone or Apple Mobile Device depending on the version of the driver installed.
4. Right-click Apple iPhone (or Apple Mobile Device) and choose Properties from the shortcut menu.
5. When the Properties window opens, select the Driver tab.
6. Click Driver Details to view more information.
Verify that the Apple Mobile Device Service is installed and running using the Services MMC snap-in using these steps:
1. On the Start menu, click Run.
2. In the Open field, type services.msc and click OK. A list of devices will be displayed.
3. View the list In alphabetical order and verify that the "Apple Mobile Device Service" status is "Started."
4. If the status does not indicate the service is started, right-click Apple Mobile Device Service and choose Start from the shortcut menu.
5. If the service is installed and started, right-click the service and choose Restart from the shortcut menu.
If the driver is installed and the service is installed and started, check the Event Viewer for error messages.
1. On the Start menu, click Run.
2. In the Open field, type eventvwr.msc and click OK. Any error messages?
Reinstall iTunes
iPhone requires a specific minimum version of iTunes. Apple recommends using the latest version of iTunes. You can check the version of iTunes you are using by choosing About iTunes from the Help menu. Visit the Apple Support Downloads page at support.apple.com/downloads/ to download and install the latest version or choose Help > Check for Updates in iTunes.
