Wipe Data using windows command line.

There are various tools out there you can buy or download for wiping hard drives, but it's easy to do this using the built-in Windows commands Diskpart and Format. Just take the drive you want to wipe out of the computer and insert it into another computer, then open a command prompt window on the second computer and type the following commands:


Diskpart


Select Disk N


In the above command N should be the disk number of the disk you are going to wipe.


Clean
{clean [all]Create Partition Primary

Use the clean command to remove partition or volume formatting from the current in-focus disk by zeroing sectors. By default, only the MBR or GPT partitioning information and any hidden sector information on MBR disks is overwritten. If you specify the all parameter, each and every sector can be zeroed, and all data that is contained on the drive can be deleted.}

Assign
Exit
Below Snapshot: 

 Now type the following command where X is the drive letter assigned to the new partition using the Assign command above:

Format X: /p:1 /v:CleanDisk /y

By scripting the above series of commands you can easily wipe all data from the drive in a single pass.


Source:

• By Mitch Tulloch ( seven-time recipient of the Microsoft Most Valuable Professional (MVP) award and widely recognized expert on Windows administration, deployment and virtualization.)
• http://support.microsoft.com/kb/300415
• http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/diskpart.mspx?mfr=true