|To the great but bucket in the sky!|
When files are deleted from the recycle bin the directory entry is deleted, the space occupied by the file is released for further use and eventually it will get overwritten by something else. Exactly what happens is dependant on the file system in use, FAT32 or NTFS.
It is possible to recover a file deleted from the recycle bin but you need recovery software to do it and it doesn't always work, especially if you have used the computer much since the file was deleted. It will have been overwritten with other information.