My Nexus 5 has never been able to transfer files over USB to Win7 computers. The computers do not recognize the presence of the Nexus (no response and nothing in Device Manager). The Nexus shows it's charging, but that's it. I've tried different cables and computers. In addition, NFC and Beam also do not work but regular WiFi works fine for internet use. Bluetooth works but is too slow to be usable for data transfer. Ideas?