networking 2 computers

I have two computers that I am running Linux on. I do not have a modem on either one. I have gone through both Net Config and Linux Config and put in all the required information, at least I think I did. I am running RH7, and using both their web site (from a third computer with a modem) and a teach yourself RH book, but to no avail. When I try to ping the other computer, I get a "network is unreachable" message. Can anyone offer me some suggestions? Please note as well, I am a newbie... so go easy.
Thanks.

ok, loads of things to try..... whoooooppeeeeeeee

Firstly... two machines.... right, you ARE using the right cable aren't you?? 90%+ network cables a patch cables, and not box to box cables. they are wired differently, and WILL NOT CONNECT TWO MACHINES TOGETHER DIRECTLY!! How to check.... make sure that the order of the wires on each plug are NOT in the same order. the (usually) green and orange pairs should be swapped round, if so that should be the right cable if not

a) get a stanley knofe and get at it.
b) buy a new cable.

assumimg that's not the case...

ok, more info first please, post the output of 'route' from both machines here, this program shows how networks are set up on each machine.

Also, post the contents of /etc/sysconfig/network-scripts/ifcfg-eth0 on both machines.

Also.... make sure /etc/init.d/network restart says [ OK ] on all counts.

that info should provide most of what we need for a simple problem.