While installing a dual-boot of Ubuntu, one of the annoying things that you’ll right away see that Ubuntu is set as the default operating system in the Grub loader. There’s an simple method to bring it back to Windows as default.

To modify, first to boot into Ubuntu, and after that run the following command:

sudo gedit /boot/grub/menu.lst

Look for 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.
default 0

The last one line is the important one. You are required to reset the value to 0 to go with the Windows boot section. Usually its 4 on a default dual-boot configuration. Reset this value to 4, and after that save and restart the system. Go into Windows in place of Ubuntu involuntarily.

The blocks at the end of the file go with the items in the menu. One can reset this value to go with whichever item he or she want as default, just keep in mind that numbering begins at 0.