When you say you checked in Disk Management, where? An empty new HDD will only show up in ONE place - the LOWER RIGHT pane of Disk Management. Moreover, that pane SCROLLS so you can see all your hardware devices. If the new drive shows up there, then you can proceed to the two-stage process of Partitioning it and Formatting the Partition(s) you create. But if it really in not in that Lower Right (scrolling) pane, you could have a faulty piece of hardware.