Nokia Lumia 1520 - The cable connection between my Lumia phone and computer does not work

1. Restart your computer and the phone.

2. Make sure that your computer is not behind a firewall or on a corporate network to complete next steps.

3. Check that you have the latest updates installed on your computer (with the phone connected), use your computer's Internet Explorer and go to www.update.microsoft.com. If you have Windows XP, you need to have Service Pack 3 and Windows Media Player 11 (or higher) installed.

4. Allow Windows install updates as they become available. On your Windows PC, go to Control Panel > Windows Update. In the left pane, click Change settings for accessing related options.

5. Disconnect your phone and other USB devices connected to your computer.

6. Make sure that your phone has enough battery power and then switch off the phone. Connect a compatible USB cable first to the phone and then to the computer end. If the connection was successful, your phone will automatically switch on and the drivers will load.

7. Enter your phone's lock screen password if prompted, then you should be able to see your phone in Windows Explorer and Windows Media Player.

8. If your computer can detect your phone but cannot load the driver, you may need to uninstall and update the drivers related to your phone in device manager:

  1. On your computer, press the Start button, type Device Manager and press enter. Leave your phone connected to the computer while uninstalling the phone drivers.
  2. Expand the Portable devices and Universal Serial Bus devices categories and uninstall all devices relating to your phone with right click.  
  3. A dialog will pop up asking you to confirm uninstallation. If you also have the option to delete the driver software, select that.
  4. Once you have uninstalled all of those; disconnect USB. Restart your computer if prompted.
  5. Reconnect USB, and wait while the computer detects the connected device. Open Device Manager and check the device status.