If that drive is making a clicking noise and not being recognized, the drive has probably failed. I presume, from what you said, that the dirve is not recognized in other systems as well? Generally, it is not the external case. If you have an another Hard drive lying around, regarless of size, put it in the ext. caddy and see if that drive is recognized. If not...it's the caddy...if it is...it's you HD.
Noli Nothis Permittere Te Terere!!
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