Repair or Reinstall Grub boot loader on dual boot Windows & Linux

Update Windows system on dual boot machine with Debain 10. Boot menu disappear after updating or replacing Windows 7

To make Grub Boot Loader working again:

visit: https://stackoverflow.com/questions/39685910/how-to-install-grub-after-installing-windows-10

Boot from Linux Live CD Ubuntu/Mint or any other

1. mount your Linux installed partition to some mount point. here XY is the number of your Linux distro partition.

   sudo mount <root-partition[e.g. /dev/sdaXY]> <mount-point[e.g. /mnt/]>
   

2. Now bind some essential live root partition directories to mounted root partition at /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
   

3. Now, change the root to newly mounted partition directory.

   sudo chroot <mount-point[e.g. /mnt/]>
   

4. Now, install the GRUB using grub-install command at your HDD MBR.

   grub-install /dev/sda
   

5. Finally update the grub entries to show newly detected partition operating systems.

   update-grub
   

6. And at last unmount all the binded partition directories, and then reboot.

   sudo reboot