You can find out which kernel you are using with uname. At a terminal type uname -a It will tell some stuff about your kernel.
Modules are a part of the kernel. I general when you compile a kernel, you will either compile it with something built in or as a module. The standard kernel has support of lots of hardware. But to make it small in size (ie to be able to fit it on a floppy disk) and for some stability issues most things are made as modules with only the essential stuff compiled in. So when you need to use a certain bit of hardware you have to load the module. One of the tools for this is modprobe.
After a quick search on the LQ HCL I found
this . I know it is not exactly your motherboard but it has the same ethernet adaptor on it. And it tells you which module it uses, which it forcedeth.
So to try and see if this works do the following.
Close any programs that you have running and exit X. This is just in case something horrible goes wrong.
Now hope fully you are at the cli. And you should be logged in as root.
Now run the following,
modprobe forcedeth
(This will load the module)
/etc/rc.d/rc.inet1 eth0 start
(this will rerun the rc.inet1 script, but only asking it to start eth0)
With a bit of luck you should now have eth0 up and running. To check this run ifconfig.
You may notice however that when you reboot the module won't automatically reload. To make it do this you need to edit rc.modules, this is located in /etc/rc.d. This is one of the scripts that are called on start up. If you read through it it will help you understand how linux works.
Now to make this module load at boot time you need to add the line,
/sbin/modprobe forcedeth
However you can not just add it at the beginning. In shell scripts the first line must be #!/bin/sh
Next there is some comments. these are the bits with a # at the start of the line. If you continue look down you will come to,
### Update module dependencies ###
Continue down , the last two lines of this section are,
/sbin/depmod -A
fi
You can now add the line to load your module. But you should note that the order which the modules are list is the order they get loaded. So you add any more in here remember that if a module is loaded and it depends on one that is further down the list things may not work correctly.