Just bought an externall hard drive and plugged it into USB port. Tried Control Panel - Install New Hardware and it said the device is working properly. The problem is that it does not show up as a separate drive on My Computer. So therefore I can't get the use of it. Yes I did restart the computer.
Try, turn your computer off, then unplug the USB cable and then the power to the drive. Restart you computer, plug the power into the hard drive, wait 10 seconds and then plug the USB into the computer. This clears the hard drive buffer. See if the drive shows up in disk management.