Simple File Shredder is a utility that securely deletes your files so they cant be restored using recovery software.
When you delete a file using the conventional Windows delete method, the file is not actually destroyed. Windows simply acknowledges the file is no longer needed and considers it free space. The deleted file will exist in a recoverable state until its over-written with other data.
When you use Simple File Shredder to shred a file, the file is over-written with with random bytes before its deleted. If the file was ever restored using recovery software, it would be worthless. Simple File Shredder can also shred free space on multiple drives to securely remove files already deleted through Windows.