A few weeks ago a student wanted to know how to undelete files on a FAT-formatted thumb drive. I knew I used to be able to do that with a Linux system--no guarantees of reliability of course--but a quick search turned nothing up. Actually, it's easy: just install testdisk, https://launchpad.net/ubuntu/+source/testdisk . To run, you may have to be superuser. It installs easily and works well (n of 1 study) on Mint 13, but any Debian-derived system is probably fine.