Hey there, Ahmed.
Is this a SATA or and IDE drive? If it's a SATA drive, you could try connecting it to your Windows 8 computer via a standard SATA connection, to see if the same thing happens again. Different drivers could prevent the HDD to be recognized by Windows 8, I'm talking about the SATA/IDE to USB adapter's drivers. You could try to uninstall the device from Device Manager and reconnect the drive, to see if it's recognized after that, or try updating the drivers. You could also try it out with different USB ports. Have you checked if the drive shows up in Disk Management? If you haven't done that already, please check and post a screenshot of what you see in Disk Management.
Hope that helps. Please let me know how everything goes.
Boogieman_WD