I run Mandrake 9.1 on a PC.
I originally had a Ne2k 10 base T network card in the machine, which I replaced with 100 Base T card.

Now when Linux boots the card is not installed by default. I have to go into HardDrake and re-aquire the card which picks up all the original settings (IP address host name , etc) and works correctly from ther on until the next reboot.

My question is which file/s are involved in this start up process and how do I aquire the information for the coreect entries in these files.

Where would any error messaes be posted that might explain what has happened.

This occured across 9.0 -> 9.1 upgrade so it's obviously some misconfigaration on my part.

You have to edit /etc/modules.conf to load the new driver on boot. Open a console, su to root and run:

# kedit /etc/modules.conf

which will bring up the file in kedit with root privileges. Look for this line:

alias eth0 <name of old nic driver>

Replace the old nic driver with the name of the new nic driver and save the changes. The next time you reboot it should properly load the correct driver. If you have two entries for nics already there, one for the old with eth0 and one for the new with eth1, delete the eth1 line and edit eth0 per the above. Also go to /etc/sysconfig/network-scripts and see if there is a file there called ifcfg-eth1. If there is delete it. There should only be an ifcfg-eth0 and an ifcfg-lo.
The problem is that when you replace a nic, the config files for the old nic are frequently not removed so you have to do it by hand. The new nic is designated eth1 and the old/removed nic retains eth0. Making the above changes should correct that.