[tkmd]

My dad needs to return his laptop to his company and would like to delete emails / documents securely. He trashed them already so I'm not sure how to delete these items securely once they have been trashed (deleted). Are there any programs or methods that can be recommended he use?

[OreoCookie]

I would low-level format the harddrive. This can be done with standard harddrive test utilities. It will take a while, but it is equivalent to choosing `write 0s' in Disk Utility.

Afterwards, he may need to re-install Windows, if the company wants a working laptop back.

[tkmd]

Formating the HD is a last option for him... If it comes to it where would I find the standard hard-drive test utilities?

[OreoCookie]

Depends: some of the manufacturer tools only work for harddrives of their own making, other are more liberal. I think Hitachi's Drive Fitness Test is one of the more liberal tools out there (in the sense that they don't insist that you have a Hitachi harddrive to be able to run it). It comes as a CD image which can be burnt as such by Disk Utility (be careful: you need to burn it as a CD image!). It comes with a low-level formatting utility.

If I were you, I'd ask your dad to ask his company if it matters if he flattens the contents of the harddrive. I reckon they'll reinstall everything from scratch anyway.

[moep]

I would recommend DBAN - Darik's Boot and Nuke
You burn the iso, boot from the CD and the disk cleans the HDD of your choice. Very straight-forward and reliable.

Alternatively you could overwrite all remaining free space on the drive with pseudo-random bits multiple times, that would ensure that none of the already delated files can be restored.

I'd use "dd if=/dev/urandom of=/tmp/wipefile bs=1M" to do this on OS X and Linux, since your PC runs Windows you'll have to look into other solutions (or boot from a live cd).

edit: You can actually a few links for recommended Windows-software on the bottom of the DBAN homepage.

[OreoCookie]

Cool, thanks for the software link