How do I make /dev/sda3 my boot partition?

Question

I have three NTFS partitions as specified below.

Device                                                 UUID                     Boot 
/dev/sda1                                             2af4c64ff4c61cc7           * 
/dev/sda2                                             1c58cb9c58cb72d6
/dev/sda3                                             c8ece40bece3f21c

When I boot to Ubuntu 12.04 I get the below error

Error: no such device  262047AC20478233
Error: File not found
Error: No such disk
Error: You need to load the kernel first

Press any key to continue 

262047AC20478233 is referring to a partition from which I have captured Ubuntu using imagex.

By using the 'e' option to edit the commands before booting, I change the UUID to c8ece40bece3f21c (/dev/sda3) which has the Ubuntu 12.04 OS ans then it boots up all fine.

How can I change /dev/sda3 as the default boot partition so that I don’t have to edit the UUID manually every time I start my machine.

I am new to Ubuntu. Please advise.

Answer 1

To fix this error you have to type just a Command.

First log on your system. Open terminal by ctrl+alt+t. Type

sudo grub-install /dev/sda3

You will asked password, give it. It will install grub on /dev/sda3. After it you will get message that grub installation successful.

Reboot your system.