I have a Samsung SATA HM320JI 320GB disk which died on me. It happened by itself without any physical or electrical disturbance. As the drive isn't recognized on device manager, no physical device shows up on disk manager (hardware error). Each time I attach it (external usb box,sata cable to motherboard; on different computers) I hear the drive platter spin up, a few head movement (no loud or repeating click) and platters spin down slowly. I bought an exact same HDD and swapped the controller PCB on the bottom but the results didn't change.
I have sensitive data on the drive. Any data recovery suggestions which doesn't cost thousands of dollars ?