I have a WD My Book 500GB portable hard disk. Today when I pluged it in it didn’t get powered up. Assuming power unit have brown up I deassemble the device and remove the hard disk. Then I connect it to the PC using SATA cabel and power cabel. When machine boots I heard a creek noise that I usually hear when the device power up before. But After OS get booted up I didn’t see 500Gb hard’s partitions mounted. I’m using Ubuntu LInux 11.04. Then I check Disk utility application. In there the hard disk is listed under PATA host adapter. It days devide is healthy. But the problem is disk is unallocated. Does this mean that my data have been lost? I have lots of valuable data on the disk. If so how can I recover them.