If have lost your grub after installing some other OS or some files have been corrupted in Linux,
here is a solution..
This is only for those who have installed ubuntu upt0 9.04 distro’s
insert any ubuntu live disc not above 9.04 and open live session.
open terminal type “sudo grub”
a new window will come with “grub>” as user.
in That type “root (hd0,”x”)”
where x is the partition number in which u have installed Linux in your PC.
this is to set the primary file system as the root file system of the linux OS.
then type “hd0”
and then restart your system.