We’ve all been in need of securely wiping a hard drive before - Either selling an old computer, or donating it to a charity.  Either way, you want to make SURE that all of your private data is gone before it leaves your hands. 

DBAN’s Boot and Nuke is your solution!  Coming in many different bootable formats, this is THE way to protect yourself before ditching a drive.  I personally like the bootable CD image - but make sure you label it with a big warning!  You don’t want someone coming by and booting your machine to this by accident!