It just means that you have two LAN ports. Typically, a motherboard
will have a single LAN port. Before motherboards came with these
built-in, an ethernet PCI card was used to provide this port.
3Com 3C920B-EMB I use it for my cable Internet conection.
NVIDIA nForce MCP Networking Adapter and 1394 Net Adapter.
What can I do with these? I'm novice in computers.
The NVIDIA network adaptor can be used in the same way as you
are using the 3Com adapter. You can use either one to connect to a
switch/hub/router or in your case a modem. If you have more than one
computer they can communicate using these ports to send information
back and forth and share an internet connection.
You can use the the following link to take you to a page covering
these ideas in greater detail.
http://computer.howstuffworks.com/home-network.htm
The IEEE1394 or firewire adapter is generally used to connect your PC
to such things as digital camcorders, external hard drives, or video
capture devices. It can also be used to network computers.
