If you want to recover or undelete your deleted or lost files (photo, video, music, document, email, etc.), you can try a Windows freeware called Recuva by Piriform.
Recuva works on any rewriteable storage media you have, including internal and external harddisk, SD card, USB thumb drive, and even iPod. It is possible to recover from damaged or formatted disks too.
Beside that, it is also able to try to recover your deleted emails from MS Outlook, Outlook Express, Windows Live Mail, or Mozilla Thunderbird.
It can even try to recover unsaved MS Word document after a MS Word crash.
Using Recuva is pretty easy and straightforward. You just need to specify the location of your lost file...
... and then the file type...
... then Recuva will start to do the searching.
It will then list out the recoverable files for you to choose and restore them in a new storage location of your choice.
Beside the free Recuva, there are also paid version including Recuva Profession and Recuva Business Edition which include advanced features and professional technical support from Piriform.