Well, you could get a Linux boot disk and use that to erase the data.
Or you could completely format the disk.
But the more important question is,
FOR THE LUVVA GOD WHY????
[mod]I removed the formatting on that last line: size, color and boldness. Its already caps. Making it more noticable than that is unnecessary for what you want to accomplish here.[/mod]
EDIT BY NON-MOD: Sorry
I was trying to be ridiculously exaggerative, I know it wasn't needed