If GRUB was not installed during the Red Hat Linux installation process, you can install it afterward and it will automatically become the default boot loader.
Before installing GRUB, you should make sure you have the latest GRUB package available or you can use the GRUB package from the Red Hat Linux installation CD-ROMs. For instructions on installing packages, see the chapter titled Package Management with RPM in the Official Red Hat Linux Customization Guide.
Once the GRUB package is installed, open a root shell prompt and run the command /sbin/grub-install <location>, where <location> is the location GRUB Stage 1 boot loader should be installed.
The following command installs GRUB to the MBR of the master IDE device on the primary IDE bus, alos known as the C drive:
/sbin/grub-install /dev/hda |
The next time you boot the system, you should see the GRUB graphical boot loader menu before the kernel loads.