Undelete Deleted Files with Recuva on Windows 7
Apart from CCleaner, Piriform has released some other useful pieces of software. Among them is Recuva, a tool to save and undelete removed data.
Files you delete are not physically removed from your hard drive until they are overwritten by new data, which makes it possible to retrieve them as long as nothing new is written on their clusters - this also includes removing data or wiping hard drives with special software such as CCleaner since they take care of deleting data properly by overwriting their hard disk space (this method is used to make deleted data inaccesible).
After checking for deleted files, make sure to go through the list for your wanted files carefully since their filenames may have changed like in the screenshot above.
You can download Recuva here: http://www.piriform.com/recuva
Like for CCleaner, there is also a portable version: http://www.piriform.com/recuva/features/portable-version