Computer help forum: SOFTWARE FOR WIPING OUT HARDDRIVE

..There are others available but both the programs below can be placed on floppy discs or CDs and will wipe ALL data from the hard drive, including the operating system. After placing the program on the disc, you'll need to boot from the floppy or CD, then run the program using the instructions at the site.

Dban (The free version includes multiple erase options including a DoD wipe routine.)
http://www.dban.org/

Killdisk (The free version of Killdisk only writes once to the drive so it's not a full DoD wipe unless you purchase the product... but multiple passes using the free version, in effect, perform a similar, effective disc wipe.
http://www.killdisk.com/

Hope this helps.

Grif

There will be nothing of useful value left on the harddrive after you run one of these programs.

Basically, EVERYTHING is removed from the drive which is wiped. Yes, the computer will power on and the BIOS will still function as it should, assuming it functioned before you wiped the drive. (You'll see a POST screen) You'll need to reinstall an operating system, drivers, and all other programs, FROM SCRATCH, if you want the computer to perform as expected.

Hope this helps.

Grif

1. Delete your personal files normally through Windows.
2. Boot up a Linux live CD. Make sure it's one that will automatically mount your internal NTFS hard disk as read/write. I think Ubuntu does that these days.
3. Go to Places > Computer and double-click on Filesystem. Go to the "media" folder. Your hard disk will be inside one of these folders. Make a note of which one it is.
4. For our purposes, we'll assume that it's in a folder called "sda1", inside "media" on the Filesystem. Go to a terminal (Applications > Accessories > Terminal) and type the following:

sudo dd if=/dev/urandom of=/media/sda1/deleteme.dat

This will create a file called "deleteme.dat" inside your hard drive. It will take up all the free space on your disk, thus overwriting all deleted files. After it has finished, go to the file browser again and delete the "deleteme.dat" file.

If you want to, run the command again to re-overwrite the free space on your disk. You can run the command again by going to the terminal window (assuming you haven't closed it), pressing the up arrow to make it appear, and then pressing Enter.

MAKE SURE YOU DELETE THE DELETEME.DAT FILE BEFORE BOOTING WINDOWS AGAIN otherwise Windows will not have any free disk space to start up in.

If you don't care about the os, DBAN is a great tool. If you want to keep the operating system intact for future use, I like Eraser (http://www.heidi.ie/node/6). It will erase files, folders, empty space, or even entire disks. I usually delete everything that I want gone, (don't forget windows settings and password files, MRU files, empty the recycle bin, temp files and folders, and that sort of info) and erase the unused space, then defrag and erase the unused space again. You may miss a few items, but you can still use the computer without needing to reinstall the os. Unless you have some critical info on the computer (online banking info or medical info) you can afford to have a few files left behind. It all depends upon your security needs.
On the other hand, if your computer is more than 3 or 4 years old, DBAN and the installing Ubuntu is probably the best thing that you could do for it!