Sometimes for some reason when you installed Microsoft Windows or other operating systems, your GRUB installation will be overwritten. This will cause your Ubuntu operating system unable to boot.
Here’s how to solve the problem using Ubuntu LTS Live CD:
1. First boot the Ubuntu Live CD from your computer
2. Then, open terminal-emulator application, and add boot-repair application to Ubuntu repository
$ sudo add-apt-repository ppa:yannubuntu/boot-repair
3. Update repository and install boot-repair
$ sudo apt-get update
$ sudo apt-get install -y boot-repair
4. Then run boot repair by typing “boot-repair” at the bash prompt
To begin repairing/reinstalling GRUB, click on “Recommended Repair” at the application screen:
The “Advance” button offers other option that lets you customize the boot option.
Boot-repair lets you to:
1. Reinstall GRUB bootloader
2. Change the default OS to boot
3. Place boot flag on any partition or devices.
4. Add extra kernel option
5. Restore MBR (only when necessary!)
6. Repair filesystem (only when necessary!)
Official Boot-repair website: http://sourceforge.net/p/boot-repair/home/Home/
Ubuntu Community Page on Boot-repair: https://help.ubuntu.com/community/Boot-Repair
Some distro like Ubuntu installs a plain white on black color scheme of GRUB on your computer. Nothing wrong with it, only it look like as if the computer is running with a monochrome monitor. Rest assured, there are ways you can do to spruce up your GRUB menu
Add colors to GRUB menu
The easiest way is to add colors to the plain vanilla grub menu. First edit the /boot/grub/menu.lst using your favorite editor.
Then, uncomment the line
# color cyan/blue white/blue
GRUB Color Explanation
cyan/blue = color of the GRUB menu
whte/blue = color when a particular menu item is highlighted
It follows this format : foreground/background … cyan/blue
Finally, save the file and reboot. You shall see your new colorize GRUB menu. Other color combination you might want to try are :
Foreground color :
GRUB boot menu similar to OpenSUSE and Linspire
Alternatively you can use themeable GRUB boot menu similar to those of OpenSUSE and Linspire bootloader. To do this you need to install gfxboot and grub-gfxboot package.
Follow the instruction from ubuntuforums.org, Howto : GfxBoot ( Grub menu like suse )