Instead, you can startup your Mac from its Recovery Partition and then use its copy of Disk Utility to securely erase your hard.
[Update Nov 2014: If your Mac has OS X 10.7 or newer installed then Apple didn’t give you an OS X install disc with your Mac. The process is very similar on older versions of Mac OS X, but the screens will look a bit different.
These instructions were written for Mac OS X 10.4 to 10.6. Here are instructions on how to use Disk Utility to securely erase a hard drive connected internally or externally to your Mac.
