"This Iphone cant be used because the Apple Mobile device isnt started"????

Type " Apple Mobile Device" into the search bar at the top of this screen by "Support".

You can sync music with one and only one computer at a time.

If you sync to another, then it will delete the music from iphone and replace with content from the new computer.

I'm pretty sure this will help your problem.Hi had the same problem with my iphone my problem was the usb driver for apple that was the cause.To be exact the inf file was the culprit .
1.Go to device manager ,under usb serial bus controllers ,apple mobile device driver should be seen,If not do this first connect iphone to computer switch to camera this should start installing driver for the camera of the iphone check the portable devices in Device Manager Apple Iphone should be seen then go down to the Universal Serial Bus Controllers now you should see the Apple Mobile Device USB Driver right click on and click on update driver browse on computer for driver software
Navigate to C:\Program Files\CommonFiles\Apple\MobileDeviceSupport\Drivers\usbaapl.inf.click on this file and you should now have this working.Talk about pulling out hair for this easy fix like others before me reninstalled all the software again again for ditto.I hope this works.Let me know cheers