>This command will *wipe* your Hard Disk. Your Harddisk will not have any partition or data.
Not to be pedantic, but that command only erases the MBR of a hard disk. Data is still present on the hard disk, although without a partition table, operating systems will have no way of accessing it. However, in some cases I've heard of people having to write zeros over the entire hard drive in order to get the Windows installer to work. If wiping the MBR doesn't work, I'd recommend the following command:
Code:
sudo dd if=/dev/zero of=/dev/sda
It'll take quite a bit longer than the other command, but when it's done, your hard drive will contain nothing but zeros. (Well, in theory. In practice it's impossible to completely erase a hard drive.)