Actually that info is very helpful.
It shows that you still have two previous kernel versions on your system. Including the one you want to use. All you have to do is open a terminal in root (su) and edit your grub.conf file to use the 2.6.12-1.1456_FC4-i686 kernel as default. The grub.conf file is located in /boot/grub. So, as root (su), using a text editor such as gedit (Gnome) or kate (KDE) type:
gedit /boot/grub/grub.conf for Gnome, or
kate /boot/grub/grub.conf for KDE
This should open the grub.conf file. Now you need to modify the line
default=0 to select the kernel you want. The kernels boot in the order they are listed, starting with 0, then 1, then 2....and so on. The default number is what chooses the default boot kernel and the kernel line to look for is the line:
title Fedora Core (2.6.12-1.1456_FC4). Therefore, if the 2.6.12 kernel is the second kernel in the list then the 'default=' line should be changed to
default=1 , if it is the third kernel in the list, the 'default=' line would be
default=2...Remember, counting starts with 0 not 1. Now save the grub.conf file, reboot and the kernel you selected will be the one that boots.