Removing GRUB or Linux Bootloaders

If you want to clean both the bootloader and the partition table, the following line will do the trick:

dd if=/dev/zero of=/dev/sdX bs=512 count=1

There "sdX" should be replaced by "sda", "sdb", "hda" or another equivalent device node corresponding to the hard drive you wish to delete. You can find it by using the command:

fdisk -l

To remove just the bootloader from MBR, do:

dd if=/dev/zero of=/dev/sdX bs=446 count=1