I never use grub for booting windows but it is described in grub
documentation in info format. For Debian GNU/Linux a file grub.conf
may have such a format.
label=Linux
root (hd0,5)
kernel /boot/vmlinuz-2.2.20 ro root=/dev/hda6
I can make a mistake, for to be sure type find /boot/vmlinuz-2.2.20 or
other version. It will show a root partition (hd0, number)