iTunes won't recognize my iPhone 6, my brand new Nano, or my older nano - Tried everything suggested

My iTunes hasn't been recognizing any of my devices for around 2 months now.. I've tried everything that's been suggested to try and fix the problem. I've even checked my own software and system, and updated what needed to be updated. I've also tried different cables and tested all of my USB Ports and it still won't recognize any of my devices.