[CentOS] Centos 5.5, not booting latest kernel but older one instead

I've been going along not noticing things happening right under my nose.
so imagine my surprise when I discovered last night that my Centos 5 box
has installed multiple new kernels over the last few months, as updates
come out, and IT IS NOT BOOTING THE NEWST ONE.

grub.conf says to boot kernel 0, and 0 is the newest one. but the one it
actually boots is 6 or 8 down the list (clearly I've not been keeping 
things cleaned up, either).

Below is some info that shows the problem. Can anyone here provide
helpful suggestions on (1) why it is doing this, and more importantly (2)
how I can make it stop?

Thanks!

uname reports:  2.6.18-164.15.1.el5PAE #1 SMP Wed Mar 17 12:14:29 EDT 2010 i686 athlon i386 GNU/Linux

while /etc/grub.conf contains:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00
#          initrd /initrd-version.img
#boot=/dev/md0
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-194.11.1.el5PAE)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.11.1.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.11.1.el5PAE.img
title CentOS (2.6.18-194.11.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.11.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.11.1.el5.img
title CentOS (2.6.18-194.8.1.el5PAE)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.8.1.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.8.1.el5PAE.img
title CentOS (2.6.18-194.8.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.8.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.8.1.el5.img
title CentOS (2.6.18-194.3.1.el5PAE)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.3.1.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.3.1.el5PAE.img
title CentOS (2.6.18-194.3.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.3.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-194.3.1.el5.img
title CentOS (2.6.18-164.15.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-164.15.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-164.15.1.el5.img
title CentOS (2.6.18-164.15.1.el5PAE)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-164.15.1.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-164.15.1.el5PAE.img
title CentOS (2.6.18-164.11.1.el5PAE)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-164.11.1.el5PAE ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-164.11.1.el5PAE.img
title CentOS (2.6.18-164.11.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-164.11.1.el5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet crashkernel=128M at 16M
        initrd /initrd-2.6.18-164.11.1.el5.img

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
                       I can do all things through Christ 
                              who strengthens me.
------------------------------ Philippians 4:13 -------------------------------