Centos 5 can't boot

Im using Super Micro server, Centos 5.x, and server can't boot successfully after you run yum update. Remember edit grub.conf before reboot server, or you need go to grub menu at boot time, add these parameters to:
rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM crashkernel=auto rhgb




/boot/grub/grub.conf

title CentOS (2.6.18-164.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-164.el5 ro root=LABEL=/ rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM crashkernel=auto rhgb
        initrd /initrd-2.6.18-164.el5.img

Ethernet turn off suddenlly in CentOS 6

This only work if your server is:
02:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
03:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection and use the ethernet card e1000e



Import the public key:
rpm –import http://elrepo.org/RPM-GPG-KEY-elrepo.org
To install ELRepo for RHEL-5, SL-5 or CentOS-5:
rpm -Uvh http://elrepo.org/elrepo-release-5-3.el5.elrepo.noarch.rpm
To install ELRepo for RHEL-6, SL-6 or CentOS-6:
rpm -Uvh http://elrepo.org/elrepo-release-6-4.el6.elrepo.noarch.rpm

see this link:
click here