How to set Default Boot Option to Windows OS or Vista

To set Default Boot option to any operating system say xyz you need to edit grub.cfg file
which resides under /boot/grub directory.
boot screen will look like this...


and each options are numbered from 0 to n( 7 here )

Ubuntu,with linux 2.6.35-23-generic =0
Ubuntu,with linux 2.6.35-23-generic(recovery mode)=1
Ubuntu,with linux 2.6.35-22-generic =2
Ubuntu,with linux 2.6.35-22-generic(recovery mode)=3
Memory test (memtest86+) =4
Memory test(memtest86+,serial console 115200) =5
Windows Vista (loader) (on /dev/sda1) =6
Windows Vista (loader) (on /dev/sda2) =7

now in grub.cfg file set default="7" to keep default boot windows vista
and to keep ubuntu as default boot
set default="0"