During the re-install, were you following the install guide?
-The install is a 2 step process: the OS install and then the amp-install portion. Did you successfully run through both portions of the install?
If so, what was the last few lines of /root/amp-install.log?
If the install steps were completed, then next is to check to make sure that the OS detected the NIC:
# ls /etc/sysconfig/network-scripts
You're looking for ifcfg-eth0
# cat /etc/sysconfig/network-scripts/ifcfg-eth0
If you're not seeing the network setup, make sure that the NIC card is running:
# service network restart
If the NIC is running, you can try re-running the amp install step:
# cd /root
# ./amp-install
Last alternative would be to reinstall again and make sure the NIC is detected during the install. (possibly reseat the NIC card)