TCP/IP

TCP/IP
How does one setup two TCP/IP protocals on a WIN98 system? Laptop used at work to get on the network with specific IP/DNS/WINS
Then to take it home and place it on a Cable network requiring specified IP/DNS.
I added two TCP/IP protocalsand it over writes the DNS on both. Is there another protocal or a way to have two? Without adding two network cards?

thanks