need a little help in installing the boot loader

[Pubudu]

I have 2 linux distros installed in my system. Fedora core 3 and Mandrake 10.0.
 + Windows Xp.
I had to reinstall Windows Xp since the system got corrupted due to some virus.

After that the boot loader i had installed before (Grub of Fedora core) is gone.
So i tried to install the boot loader of  Fedora core 3 but i couldn't do it.
Later i installed the boot loader of Mandrake.Now i can start Fodora.

But i need to install the boot loader of Fedora.(grub)

Can anyone tell me the steps to do it.