There are many ways but a favorite way is to boot any Linux LiveCD and to use the syslinux package like so: Just change the "sdx" to your sd for example /dev/sda or whatever the drive is that is supposed to boot Windows. sudo dd if=/usr/lib/syslinux/mbr/mbr.bin of=/dev/sdx 0+1 records in 0+1 records out 440 bytes copied, 0.0197808 s, 22.2 kB/s........