at first get in the bios of the pc and see if the hard disk is recognized. if is ok, then see if is recognized by windows. if not, check if windows show the drive in the device manager. r-click (on my computer) ->properties -> hardware-> device manager. (under disk drives). if this is ok, the problem is that the drive doesn't have a partition. this is the reason why you don't see it in my computer. if is not recognised even in bios or device manager, then you have a serious problem with the drive... electronic problem, or something burned...
reply again for any news.. good work!