grub2 - Duplicate grub menu in Ubuntu 12.04

I have a problem with my laptop grub menu. duplicate menu appears as below:

Found linux image: /boot/vmlinuz-3.2.0-24-generic

Found initrd image: /boot/initrd.img-3.2.0-24-generic

Found linux image: /boot/vmlinuz-3.2.0-24-generic

Found initrd image: /boot/initrd.img-3.2.0-24-generic

how to remove duplicates? I use ubuntu 12.04.

Try sudo update-grub in a terminal. That might help.