Many students and friends keep asking me for a free hard drive wipe tool, I found this one may be useful for yours.
http://www.terabyteunlimited.com/copywipe.php
CopyWipe™ is a utility for copying or securely overwriting (wiping/erasing) entire hard drives. CopyWipe can ease and expedite the transition to a new hard drive by copying the entire contents of one drive to another. CopyWipe can also help prevent confidential or private data from being recovered, by securely wiping the contents of a drive. A number of options are provided for wiping, most of which exceed governmental standards (such as DoD 5220.22-M, NAVSO P-5239-26, etc.); this allows the user to choose an optimal balance between security and duration of the wiping operation.