A:Please follow below steps to install your Linux CentOS 5.2 installation.
1.Disable the Onboard LAN 1 and Onboard LAN 2 in BIOS setting.
2.Enter Boot menu and starting the Linux CentOS 5.2 installation.
3.Please install the system packages like below picture.


4.After install CentOS 5.2 completely , download your LAN driver by following link.
Link:http://www.realtek.com/downloads/downloadsView.aspx?Langid=1&PNid=13&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false#2
5.Please remove the in-box driver and remove the r8169 LAN driver by following command.
# cp -p r8168-8.011.00.tar.bz2 ~
# cd ~
# tar vjxf r8168-8.011.00.tar.bz2
# cd /lib/modules/`uname -r`/kernel/drivers/net/
# rm -f r8169.ko
# cd ~
# cd r8168-8.011.00
# make clean
# make modules
# make install
# depmod –a
# reboot
6.After upgrade your LAN driver complete, please reboot your system and enable the Onboard LAN 1 and Onboard LAN 2 in BIOS setting.