A. List your current menu items

sudo update-grub 

B. Edit setup file

sudo gedit /etc/default/grub 

Set the boot default to your Windows boot partition (eg.)

GRUB_DEFAULT=”Windows 7 (loader) on /dev/sda1?

WARNING: Just setting 'GRUB_DEFAULT=n', will NOT work after kernel updates, etc.

(Save the file and close.)

C. Update grub settings

sudo update-grub 

Now, on boot, you will AUTOMATICALLY default to MS Windows.

PART 2: (Optional Extra)

Hide the Grub2 menu, and use the default menu option.

Description: This both hides the startup menu, and shortens the (usually 10 second) timeout. The PC will auto-launch whatever the default option is on startup.

NOTE: The user just needs to hold down the Shift key (on startup), to again see the Grub2 menu.

STEPS:

D. Edit setup file

sudo gedit /etc/default/grub 

Uncomment the line '#GRUB_HIDDEN_TIMEOUT=0', to look like:

GRUB_HIDDEN_TIMEOUT=0

(Save the file and close.)
E. Update grub settings

sudo update-grub 

Now, on boot, you will AUTOMATICALLY boot to the default menu option, UNLESS you hold down the Shift-key at boot time. Then the grub2 menu will re-appear.