GrUb 9.10

Make a back-up

sudo cp /boot/grub/grub.cfg /boot/grub/grub_bckp.cfg
sudo pico /boot/grub/grub.cfg

Now you will see that appear some lines, like when you use nano

### BEGIN /etc/grub.d/00_header ###
if [ -s /boot/grub/grubenv ]; then
  have_grubenv=true
  load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
  saved_entry=${prev_saved_entry}
  save_env saved_entry
  prev_saved_entry=
  save_env prev_saved_entry
fi
insmod ext2
set root=(hd0,7)
search --no-floppy --fs-uuid --set 9aa1c56e-f513-4fbc-a76a-7ca96eff316d
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=640x480
  insmod gfxterm
  insmod vbe
  if terminal_output gfxterm ; then true ; else
    # For backward compatibility with versions of terminal.mod that don't
    # understand terminal_output
    terminal gfxterm
  fi
fi
if [ ${recordfail} = 1 ]; then
  set timeout=-1
else
  set timeout=10

LoOk at this lines:

set default="0" Select your SO
set timeout=10 shows time out to inicialize your SO

In each case you should to choose the SO that you want to Inicialize, only has the place of Windows 7 in grub least 1

Ubuntu, Linux 2.6.31-14-generic
Ubuntu, Linux 2.6.31-14-generic (recovery mode)
Memory test (memtest86+)
Memory test (memtest86+, serial console 115200)
Windows 7 (loader) (on /dev/sda1)

You can see that Windows 7 is in the fifth position
5-1=4

### BEGIN /etc/grub.d/00_header ###
if [ -s /boot/grub/grubenv ]; then
  have_grubenv=true
  load_env
fi
set default="4"
if [ ${prev_saved_entry} ]; then
  saved_entry=${prev_saved_entry}
  save_env saved_entry
  prev_saved_entry=
  save_env prev_saved_entry
fi
insmod ext2
set root=(hd0,7)
search --no-floppy --fs-uuid --set 9aa1c56e-f513-4fbc-a76a-7ca96eff316d
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=640x480
  insmod gfxterm
  insmod vbe
  if terminal_output gfxterm ; then true ; else
    # For backward compatibility with versions of terminal.mod that don't
    # understand terminal_output
    terminal gfxterm
  fi
fi
if [ ${recordfail} = 1 ]; then
  set timeout=-1
else
  set timeout=5

ThanKs http://www.ubuntu-es.org/