To network you need the folowing equipment:
more than one computer
for every computer you have they need a network card (wireless or otherwise)
If you have more then one computer then you need a hub
If it is just 2 computers then you need just a crossover cable (which plugs directly into each computer.
If you have broadband you can share the internet with either a modem connected to any pc or one connected to the hub. Hub with built in modems are called routers and this is the preferred method if you have more than 2 computers as anyone at any time can surf the net without being reliant on another computer.
Once you have set up your network, you will need to configure windows.
This is the fun part and probably the reason why so far you have failed to make your net - work (excuse the pun )
If every computer has xp then, great as this will make life soooo easy for yourself. One thing you have to make sure is that every computer is on the same workgroup (you can set this up by right clicking on my computer, clicking properties and hitting the computer name tab) THEY ALL MUST BE ON THE SAME WORKGROUP TO SEE EACHOTHER. you might have to reboot.
I won't go into further detail however until you tell us what configuration you have as this reply could get very long...
I need to know what os u have on each comp, what hardware you bought, have many computers, etc etc