If lsmod does not list an ethernet device, does that indicate a problem with the onboard card, or is it a driver problem? Have installed Slackware 12.0, not sure what the motherboard is, as machine is second-hand.

No. lsmod is not supposed to list devices.

Try ifconfig and lspci.

sorry, meant lspci

Check dmesg

Yes - check your syslog (dmesg) after boot to see if there are any problems -- however, some bioses allow the interface to be switched off or provide special leep states for them. The interface may just not be connected to the bus.

Of course, there is always the possibility that you do not, in fact, have an ethernet device. Presumably you have an ethernet port? Presumably you do not have working ethernet? (These may seem like silly questions - however, experience tells me to check these things.)

Did you ever have working ethernet?

Off your original post - it is unlikely to be a driver problem - eg. devices with no driver at all still appear in lspci. The list depends on the content of the device ROMs.

Thanks for your help, it is now up and running after upgrading to slackware 12.2

Not sure what the problem was, but ethernet was not present after rebooting from time to time.

Most likely an acpi thing then - the latest slackware will have included updated to this.

I'd still check the bios to see if the ethernet has any built-in power management features. The kernel is often better at handling these things so it is usually more effective to switch these off.