First, right-click the Start button then click Disk Management, does it show there? If so it should have a drive letter assigned before File Explorer [Windows Explorer in earlier versions of Windows] can see it. Second, have you tried the USB cable in different ports? One variable is that not all things USB 3 will fall back to USB 2. Sometimes after trying different ports it helps to reboot the computer. I have seen where pulling the power cord out of the computer for awhile helps, tends to 'normalize' things.