Aww, your no fun for the hands of a malicious person with the capability to restore previously recorded and deleted data! Simply erasing all the data on your hard drive and formatting.
Obviously, the easiest way to go about it, if your choosing to get rid of the hard drive is to physically smash it around it's headers.
A government formatting is wiping it 7 times over, the data becomes barely readable and almost impossible to recover.
Shred formatting overwrite the original a number of times (again 7 is the magic number for most) before zeroing out all the data.
Look for 'disk wiping software' like:
http://eraser.heidi.ie/http://www.diskwipe.org/http://www.killdisk.com/http://www.dban.org/In your case since your already got Eraser, that's a pretty good free one.
