When you install a dual-boot of Ubuntu, you will notice that Ubuntu is now set as the default operating system in the Grub loader. Most of the users don’t want Ubuntu as the default OS for their systems. To make the windows as default OS, you will need to change in the boot menu list.
To make this change, you’ll first have to boot into Ubuntu, and then run the following command:
sudo gedit /boot/grub/menu.lst
Find this section of the file:
## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not change this entry to 'saved' or your
# array will desync and will not let you boot your system.
Change “default 0” to “default 4”
You will need to change that number 0 to match the Windows boot section.In most cases 4 is a default dual-boot configuration and in one my friend’s laptop this value is 5 so you need to check this and enter the value.The blocks at the bottom of the file match the items in the menu and the numbering starts at 0.
There is one more easy way of doing this :
Use startup-manager,below the “Boot options”,you can make a choice with “Default operating system”,choose windows XP, and all done!!
Note : If you don’t have the start-up manager. You can install it
sudo apt-get install startup-manager
Happy booting !