if the drive is clicking, and doesn't show up in disk management, then it has most likely failed. if you need data off the drive, you will need to do data recovery. however, if the drive isn't getting enough power it might click, also. disconnect the data cable, plug the power adapter directly into a wall outlet, and see if it spins up without clicking. if it does, then plug the drive back into the pc to see if it shows up. if it doesn't then it's failed and needs to be replaced.