Windows+ubuntu dual system reinstalled windows after the boot repair

today reinstalled windows 7 in the notebook, after the boot directly into the windows, no linux options, solution: 1, find a linux liveCD CD or U disk Do a U disk boot 2, enter the liveCD of linux, open the terminal, ww.dnzg.cn execute the sudo passwd root command to set the root password, then switch to root 3, use fdisk -l to list the disk list, find the Linux partition, I The boot is a separate partition, is sda9, depending on the personal computer situation 4, execute mount /dev/sda9 /mnt mount it 5, execute grub-install -root--directory=/mnt /dev/sda command to install Grub, reboot restart after completion, boot boot will be restored