Recovering grub after installing windows 7 on Ubuntu

To recover grub:

1. open the live version
2. open the terminal and run sudo fdisk -l to see where Linux is installed
3. run sudo mount /dev/sdaX /mnt where x is the number you have found Linux word in
4. run sudo grub-install --root-directory=/mnt /dev/sda to install grub
5. run sudo update-grub to update grub and if this command didn't work run it after rebooting
6. reboot

http://askubuntu.com/questions/83771/recovering-grub-after-installing-windows-7