A Computer Won't Recognize the External Hard Drive

1. Click the right mouse button on the 'My Computer' icon on your desktop and select 'Explore' from the menu. The Windows Explorer window opens and will display the hardware attached to your computer under 'hard disks drives.' Your external would normally show up as 'E:' or 'F:' depending on how many installed drives you have. If it does not appear on the list of hard drives on your computer, examine the hard drive to see if there is a green LED light on.
2. Look at the light to see if it is flashing orange and green. If the light is flashing, this can point to faults with the external drive or indicate that it is not communicating with the computer. Move your mouse to the bottom right of your screen and examine the system tray near the clock. You may note there is a 'safely remove hardware' icon in the system tray. Right click that icon and click 'safely remove hardware'.
3. Look on the list when the associated box appears and note whether there is a 'mass storage device' in the list. If there is nothing in the list, unplug the external drive from the computer and attach it again. If the computer still does not recognize the device, plug it in and reboot your computer. Some external hard drives need to be set to automatically boot with the computer. In some cases, if this is not set up, they will remain attached and appear to be connected but will not appear on the system. After rebooting, open a Windows Explorer window and see if your external drive appears on the list in the left panel.
4. Listen to the hard drive for a whirring sound. Look at the LED light for signs of performance. If you hear or see nothing, this could be evidence that the external drive is corrupted. If you hear a whirring sound or see signs of it working, but still not talking to the computer, examine the cable for the external drive. You will note that most external hard drives have a two-prong cable with USBs attached to a long end and a short end. There is a junction plug from which the short and the long plugs both protrude. Make sure the long cable attaches to your computer, with the junction plug inside the external drive.