Message on iPhone 5C showing usb cable and iTunes
I was trying to sync my iPhone photos etc. to my computer using iTunes and it locked on the screen showing the USB cable and the iTunes logo.
iPhone 5c, iOS 7.1
That means that iOS detected an internal error that it could not recover from, and needs to be restored from iTunes. Doing this will wipe the contents of the phone. You should then be able to restore your iTunes or iCloud backup.