Have you noticed that your /etc/grub.conf doesn’t link to your /boot/grub/grub.conf anymore on CentOS 6? Somewhere along the line something broke.. at least on the machines for one of my clients. Here’s how to fix it.
You can simply run these commands as root to get things back to normal, then reboot to come up under the new kernel:
mv /boot/grub/grub.conf /tmp/grub.conf.old
mv /etc/grub.conf /boot/grub/
ln -s /boot/grub/grub.conf /etc/grub.conf