You could try from the command prompt.
1. Log in as root.
2. use lsmod to list loaded modules. If you don't see the name of your NIC module, then it is not loaded (incorrect module selected perhaps ??)
3. If module name is listed, use ifconfig to see if eth0 is running. If not, check /var/log/messages to see if you can find a log entry that might tell you why eth0 did not start
4. If ifconfig shows eth0 as apparently working, check cables, hubs, etc.
Hope this helps.
Kelvin