In order to fix the issue, press Windows + Pause/Break key combination and open Device Manager. Expand the Universal Serial Bus controllers list, right-click the driver and select Uninstall. After that, reboot your computer, connect the MP3 player using the USB cable, press Scan for hardware changes icon from Device Manager and wait for Windows to retrieve the drivers. If it doesn't help, launch Windows Media Player, press Alt + H, click Check for updates and install the provided files. Also, check the Set up a device to sync in Windows Media Player guide provided by Microsoft.