Simple File Shredder is a freeware utility that securely deletes your files so they can't be restored using recovery software.

Simple File Shredder ensures your privacy by scrambling the filename, encrypting and overwriting the file up to 25 times with random bytes, changing the file date and time to a random date-and-time value, and verifying that the file has been completely shredded before deleting it.

Download: Simple File Shredder 2.6