mint not on grub menu!

[mrdreamers]

i installed mint 13 and in the middle of it it ask me to unmount it or not i said yes but changed my mind in the middle of it so i pushed power and started over and installed it successfully, but now it does not show up in grub i believe i unmouted the partition it was on thats why but i dont know how to fix this, i tried g-parted but it does not give me the option to mount it and mounting it from the desktop on ubuntu 12.04 works but unmounts when restated and still does not show up in grub im thinking i have to do it thru mint live cd but im noobin it still and don't know how, can someone help so i can access mint on grub ty in advanced