Recuva

Recuva (pronounced "recover") is a freeware Windows utility to restore files that have been accidentally deleted from your computer. This includes files emptied from the Recycle bin as well as images and other files that have been deleted by user error from digital camera memory cards or MP3 players. It will even bring back files that have been deleted by bugs, crashes and viruses!

Check out other free tools from Piriform: CCleaner and Defraggler.