Well to answer the real question, when you format a harddrive or even Fdisk it you are only droping the MASTER BOOT RECORD (MBR) to actually remove all data from the harddrive you need a program that will over write the current binary data on the harddrive, i.e. replace it with all 1 or 0 or some combination there of. If you look you can find such a program. I would just write my own.
cheers