How to repiar GRUB from Ubuntu live CD

Sometimes people installing new hardwares or update Linux system causes GRUB error. In case you don’t know what GRUB is, according to Wikipedia, it is a boot loader from GNU project. It is used to boot mulitple operation systems on your machine.

Now let’s go back to the GRUB error. One way to fix it is to use Ubuntu live CD.

• Insert your lived cd into the CD/DVD drive.
• Boot your machine by using the live CD. Please note that you don’t install the Ubuntu operation system. What you will do is load the live CD into the memory, so it won’t install anything into your hard drives eventually.
• Find you command line console under the start menu.
• Type “sudo grub” – Access the grub environment.
• Type “find /boot/grub/stage1″ – It will return something like (hdx, y). “x” means the number of your hard drive. “y” means the number of your partition. e.g. (hd2, 4) means your GRUB is installed on partition 4 of hard drive 2.
• Type “root (hd2, 4)” – Access the GRUB as root, I think.
• Type “setup (hd2, 4)” – Setup the GRUB on partition 4 of hard drive 2.
• Reboot your machine.

Unfortunately, I haven’t have a chance to try it myself. If there is any problem, please submit a comment to this post.