Hello. I am sure there are plenty of newbies around when it comes to linux, myself included. This is a guide of how to repair grub in the event your windows 7 removed the grub during the installation.
First thing that you'll need to do is to boot from a kali linux live cd. After that, go to gparted so that you can get to see where kali was installed: usually it's in the file system that ends with ext4, depending with the file system you used during the installation. In my case, the kali linux system was in sda3, but it varies with different systems.
From there, you'll have to use the terminal for the following commands:

Code:
mount /dev/sda3 /mnt
mount --bind /dev /mnt/dev
mount --bind /dev/pts /mnt/dev/pts
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
chroot /mnt
grub-install /dev/sda
update-grub
exit
umount /mnt/dev/pts
umount /mnt/dev
umount /mnt/proc
umount /mnt/sys
umount /mnt
This will restore the old kali linux boot loader, however, you will have to boot into kali once the live cd is out, so as to add windows into the boot loader. Once booted, go to the terminal and do the following:


Code:
os-prober
update-grub
... and thats it. hope this helps. I think this will also work with windows xp,vista, and 8, but i haven't yet tested on those systems, so i can't confirm.