[CentOS] CentOS 4.5 system doesn't boot after installing latest updates

Mon Sep 24 20:59:47 UTC 2007
Alfred von Campe <alfred at von-campe.com>

> Today I decided to install all the latest updates (including the  
> -06 kernel).  The "yum update" seems to have run just fine (no  
> errors), but when I rebooted the system it just sits there with the  
> word "GRUB" in the upper left hand corner.  I booted from the  
> CentOS 4.5 install CD into rescue mode, did a "chroot /mnt/ 
> sysimage" and reinstalled grub and the latest kernel, but it still  
> gets stuck in the same place.  It's not that I can't boot the new  
> kernel; I can't even get to the grub screen!

I'll answer my own question.  In addition to re-installing grub, a  
"grub-install /dev/sda" was required to get the system to boot.  I  
thought that reinstalling grub via yum/rpm would take care of it, but  
apparently it didn't.  Lesson learned, panic averted.