Well,If you have deleted some files and if you can't find those files in the recycle bin folder then most probably you have permanently deleted those files.
Here is a link that might help you:
http://www.techyv.com/questions/do-not-find-any-folder-recycle-bin
Here is a link that might help you:
http://www.techyv.com/questions/do-not-find-any-folder-recycle-bin