I need help with secure data deletion and data recovery?

To securely destroy data you need to do more than format. DBAN will nuke a whole drive, Eraser 5.3 can wipe specific files or free space. Those are unrecoverable except for a handful of world-cl experts. The only sure way is to physically destroy the drive. If you securely wipe some files but not the whole drive, there are other things you need to be aware of -- temp files, swap space, etc.