next time you probably want to post this in the computer hardware and driver subsection:
http://forums.d2jsp.org/forum.php?f=199but since you are already here:
For any desktop, or for network cards that have been added after the computer was manufactured:you need to find out what network card you have, so you can go to the network card manufacturer's website, and download the driver for that device
For laptops or premade computers:go to your computer manufacture's website and there will be a place to download the driver for the network card that came in your model computer.
You'll notice you have 2 options for a premade desktop above. If you need to figure out what network card you have, and you don't know how, you can try programs like "Speccy" to tell you (just google that).
Pro tip: As you have probably figured out now, a missing network driver is a major pain in the ass since without it, you can't download a network driver! Once you do find the correct network driver and get it working, burn it to a disc or put it on some kind of external media so you don't have this problem again if you ever reinstall the OS on this machine!
This post was edited by Azrad on Aug 9 2013 11:41am