If you are looking for a easy and perfect way to shred files, then Moo0 FileShredder with four different shredding options is a very good choice. Moo0 FileShredder lets you easily erase your private/secret files perfectly off your HDD. Since all of your private data is usually recoverable from Windows even after you delete it, this software will help you solve the problem as it deletes all the files beyond recovery.
All you need is to drag and drop your private files / folders onto this software. It currently supports 4 levels of erasing methods depending on how important the file deletion is to you.
In case you are running Windows explorer in administrator mode, then make sure that you run this tool also in administrator mode. It asks for confirmation of deletion of files in case you have set it.