How to Permanently Delete Email From a Hard Drive
Periodically deleting e-mail from your hard drive is a good idea to protect your privacy, keeping your private information safe from prying eyes. Delete emails permanently by using the file deletion options in your operating system, removing the file from the drive so that it can no longer be accessed from within the system. This procedure generally takes around five minutes.
Right click "Start" and select "Explore."
Click "Computer," "C," "Program Files" and open the folder for your e-mail client.
Open the folder containing your e-mails (typically labeled "Inbox").
Right click the file(s) to be removed and select "Delete."
Right click the Recycle Bin on your Desktop and select "Empty Recycle Bin." This removes the e-mail files from the drive.