This issue may becaused because the Apple Mobile Devicer driver is inactive. There are several ways you can bring it back on. And you can bring it back on in the Windows service manager.
Here is how you can re-enable the mobile device driver service.
1. Open Start Menu >> Run and type services.msc and press ok [ this will open up services ]
2. Locate the service named Mobile Device Driver
3. Double click the service to open properties
4. In the "general" tab find the "startup type" drop-down arrow menu and make sure "automatic" is selected.
5. Also see the general tab to check the "service status". If it does not say "started" then click the start button to start the service and connect your phone again and click apply.