After installed just fire up a LiveISO. I like Parted Magic.
edit /etc/grub/grub.conf
[root@localhost ~]# cat /boot/grub/grub.conf
# 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 (hd1,0)
# kernel /vmlinuz-version ro root=/dev/mapper/isw_eajhcidchc_Volume0p3
# initrd /initrd-version.img
#THE BELOW LINE WAS COMMENTED OUT AND UNCOMMENTING IT FIXED THE ISSUE###
boot=/dev/mapper/isw_baiehbdebb_Volume1
default=0
timeout=5
splashimage=(hd1,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-194.11.1.el5)
root (hd1,0)
kernel /vmlinuz-2.6.18-194.11.1.el5 ro root=LABEL=/
initrd /initrd-2.6.18-194.11.1.el5.img
[root@localhost ~]#