Reinstalling Grub

Grub is a program which used to manage operating system if you install more than one operating system in single computer, for example you install Windows 7 and Ubuntu or another Linux Operating system.

GNU GRUB (short for GNU GRand Unified Bootloader) is a boot loader package from the GNU Project. GRUB (shortened form of GNU GRUB) is the reference implementation of the Multiboot Specification, which enables a user to have multiple operating systems on their computer, and choose which one to run when the computer starts. GRUB can be used to select from different kernel images available on a particular operating system's partitions, as well as pass boot-time parameters to such kernels. (http://en.wikipedia.org/wiki/GNU_GRUB)

The conditions grub problem appear:

Install GNU/Linux operating system and then install Windows family operating system although  in different partition from existing GNU/Linux operating system.

The conditions grub problem doesn't appear:

Install any Windows family operating system and then install any GNU/Linux operating system. GNU/Linux operating system will automatically detect another existing operating system.

If the second condition happen for any reason or condition you must, the existing GNU/Linux operating system will disapper from your computer. You must reinstall the grub (if you want to use grub), these steps will lead you reinstalling your grub:

1. You need bootable CD of GNU/Linux operating system


2. Insert the CD into your computer optic


3. If live CD of GNU/Linux operating system ready open terminal program


4. Mount existing partition which installed GNU/Linux operating system
   

   root@linux#mount /dev/sda1 /mnt

   
   


5. Install grub
   

   root@linux#grub-install --root-directory=/mnt /dev/sda

   
   


6. Reboot

Assumption:

The existing GNU/Linux operating system installed on /dev/sda1