TestDisk helps fix errors, fix partitions, recover files from damaged partitions, recover lost partitions & make non-booting disks bootable again.

TestDisk’s website says the program is designed “to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software: certain types ...

Perform low-level disk repair and file recovery--from a command prompt or DOS box--with free utility duo TestDisk and PhotoRec.

This post describes testdisk, one of the tools that comes in handy for recovering recently deleted files (along with fixing partitions in other ways).