Dual System (Windows+ubuntu) re-installed after Ubuntu, repair boot

After reloading Ubuntu, restarting the machine, the Windows system disappears. Enter the BIOS to modify the boot sequence, Windows system Recovery, but, just installed Ubuntu No, a boot, the computer automatically into Windows.

Workaround:

Install the system's USB stick into Ubuntu live and open the terminal:

1. Input sudo-i

2. Find the mount point to install Ubuntu (use fdisk-l command to view), my in/dev/sda9.

3. Input mount/dev/sda9/mnt

4, if have/boot partition, need to do this step, otherwise, skip. Specifically, enter the command again on the Mount boot partition's mount point/mnt, and the format and step 3 are the same.

5, install grub, enter grub-install--ROOT-DIRECTORY=/MNT/DEV/SDA (note the space. --root and/DEV/SDA have a space in front of them)

6. If Grub.cfg is lost or grub.cfg error occurs, perform the following action (note the space):

　　Mount-bind/proc/mnt/proc

Mount-bind/dev/mnt/dev

Mount-bind/sys/mnt/sys

Chroot/mnt Update-grub

Umount/mnt/sys

Umount/mnt/dev

Umount/mnt/proc

7,reboot

Dual System (Windows+ubuntu) re-installed after Ubuntu, repair boot