setting up Networking

I have an old Packard bell with 100 mhz and 40meg. I have installed Redhat 6.2 on it so I can mess around and learn Linux. I have a 3Com Etherlink III 3c509 installed and I have went through the network setup but when I try to ping my router I get destination unreachable. When at the prompt I use “ifup eth0” I get a reply that it is delaying the starting. How can I get the connected?