There seems to be a certain bug with Debian, when installing it on the same hard drive with Windows, on the next boot, windows is not one of the options, so what you can do is this
update-grub
You will see results such as
update-grub Generating grub.cfg ... Found background image: /usr/share/images/desktop-base/desktop-grub.png Found linux image: /boot/vmlinuz-2.6.32-5-686 Found initrd image: /boot/initrd.img-2.6.32-5-686 Found Windows 7 (loader) on /dev/sda1 done
Grub should now find you missing windows and add it to the boot menu !
I wrote this for my own reference, because every time i install i spend so much time trying to find the magic words online again