TestDisk
When these symptoms are caused by malfunctioning software: certain types of viruses or human mistake, TestDisk was created to help recover lost partitions and/or make non-booting disks bootable again (such as accidentally deleting a Partition Table). TestDisk makes recovering partition tables a breeze.
TestDisk is a valuable program for recovering data from non-booting hard disks on-site. It can gather a lot of data about a drive and then send it to a specialist for additional evaluation. The features of TestDisk will assist both beginners and experts.