grub – Pupli

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

References
https://help.ubuntu.com/community/Boot-Repair

search :

/boot/grub/grub.cfg

and find something similar :

Windows NT/2000/XP (loader) (on /dev/sda1)

edit :

/etc/default/grub

and change to:

GRUB_DEFAULT="Windows NT/2000/XP (loader) (on /dev/sda1)"

finally run :

update-grub

References :
http://askubuntu.com/questions/52963/how-do-i-set-windows-to-boot-as-the-default-in-the-boot-loader

sudo mount /dev/sda1 /mnt

sudo mount --bind /dev /mnt/dev &&
sudo mount --bind /dev/pts /mnt/dev/pts &&
sudo mount --bind /proc /mnt/proc &&
sudo mount --bind /sys /mnt/sys

sudo chroot /mnt

grub-install /dev/sda

grub-install --recheck /dev/sda

update-grub

exit &&
sudo umount /mnt/sys &&
sudo umount /mnt/proc &&
sudo umount /mnt/dev/pts &&
sudo umount /mnt/dev &&
sudo umount /mnt