Before we continue about how to fix linux bootloader, first you need to know what is GRUB. GRUB or GNU GRand Unified Bootloader, as its name, bootloader, is a spesific program used to execute or to load data command when a machine is booting. In this case, the program or the data executed by GRUB is one or multiple operating systems. GRUB developed by the GNU Project and is used by the operating system based on Linux open source.
GRUB 2 is the default bootloader has been used by Ubuntu since the version 9:10 (Karmic Koala). The GRUB provides many advantages to system, especially for systems or computers with have multiple Operating System. But unfortunately the GRUB implementation is one that sometime could be considered "error". Because sometimes, when there is little change on disk partition or core of OS, GRUB often error crash or does not running at all. However, fortunately to solve this problem is quite easy. What you need is just a Flash drive or CD with contains Live Ubuntu OS. Here are the steps you can do.
1. Boot Using a Live CD or USB
2. Open the Terminal
3. Mounting Partitions Installing Ubuntu
Because many OS partition or OS installation where each OS is different, then the steps to follow in this tutorial also be dynamic. Label partitions used in the following commands hope customized with partition table of your Ubuntu installation 14:04. To check the appropriate partition labels can be done using GParted application, which is available in a Live CD or USB you. In this example we used is the drive = sda; partiton number = 1 (sda1).
sudo mount / dev / sda1 / mnt
* Adjust the parameters red colored with your table partition
4. Bind & chroot Partitions
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
sudo chroot / mnt
5. Re-install and update GRUB 2
grub-install / dev / sda
--recheck grub-install / dev / sda
* Adjust the parameters red colored with your table partition (only Drive Letter without partition number)
6. Unmount and restart
sudo umount / mnt / sys &&
sudo umount / mnt / proc &&
sudo umount / mnt / dev / pts &&
sudo umount / mnt / dev &&
sudo umount / mnt &&
After that, Do not forget to unplug or remove the installation media Live CD / USB when your computer in reboot process. Done.