Fix grub2 boot after Windows is reinstalled

When you reinstall windows with the installed version, the MBR will be rewritten, causing grub loss. You can use livecd to fix grub after it is started.

Start with ubuntu9.10 livecd and then open the terminal

If your Ubuntu/partition is sda7 and the/boot partition is sda6, start it with livecd and enter
Sudo-I
Mount/dev/sda7/mnt
Mount/dev/sda6/mnt/boot (skip this step if no/boot partition is available)
Grub-install-root-directory =/mnt/dev/SDA

As before, replace SDA with SDB if you want to mount the second hard disk.

If grub. cfg has been lost or grub. cfg has an error, You need to recreate it and continue with the following operations:

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

Exit