Scenario: You have a dual-boot setup (Windows 7 + Ubuntu 10.04LTS). But your Windows 7 crashed and you decided to make a fresh install. After reinstalling Windows, Ubuntu is gone and boot up gets you straight to your Windows installation. And GRUB2, which supposed to manage these 2 operating systems, is nowhere to be found, or worst, the screen might only show you a “grub_rescue>” black screen of death.
Well, chill out, this is a very simple issue and I have a very simple, but effective solution for you.
Simply grab your Ubuntu 10.04LTS Live-CD and run it. Once you’re on the desktop go to Applications -> Accessories -> Terminal and then follow these simple steps.
1. First, you need to find out the UUID of the partition that should contain your boot loader. In my case it’s located in my root directory (/). To do that simply type:
$ sudo fdisk -l
In my machine the command resulted in something like this:
Device Boot Start End Blocks Id System /dev/sdb2 321 5589 42312704 83 Linux /dev/sdb3 5589 9730 33262592 83 Linux /dev/sdb4 14 320 2465977+ 82 Linux swap / Solaris
To confirm your boot loader location, in the Terminal, simply type:
$ df -Th
And the result looks something like this:
Filesystem Type Size Used Avail Use% Mounted on /dev/sdb2 ext4 40G 6.4G 32G 17% / /dev/sda5 fuseblk 175G 151G 24G 87% /media/wintfs /dev/sda1 fuseblk 59G 33G 27G 55% /media/winboot /dev/sdb3 ext4 32G 14G 16G 48% /home
2. Now to prepare this partition (/dev/sdb2) for GRUB install, first we need to mount it
$ sudo mount /dev/sdb2 /mnt
If you have a different location for your boot loader e.g. /boot instead of just root (/), try it like this:
$ sudo mount /dev/sdb2 /mnt/boot
3. Now you can install GRUB2 in your boot loader partition:
$ sudo grub-install --root-directory=/mnt /dev/sdb
(Notice the partition UID number (2) has been excluded)
Again, if you have a different location for your boot loader, try:
$ sudo grub-install --root-directory=/mnt/boot /dev/sdb
4. After you have successfully installed GRUB, unmount your boot partition:
$ sudo umount /mnt
$ sudo umount /mnt/boot
5. Reboot your computer.
For more information about GRUB, please click here.