It should be as simple and finding the correct module used when you boot the CD (open a console window and type lsmod and enter key) on the Dell then when you boot the HD in the machine open a console window and use su to become root then modprobe module_needed and /etc/init.d/networking restart to restart the network with the proper module loaded and get an IP. Edit the file /etc/modules and replace the old network module already in there with the new proper one and it will be loaded on the next boot. Or you can mount the HD while still booted from the CD and change the /etc/modules on it then when you reboot the network should come up.