gambler104: go to your network connections, right click on the connection you want to use, but which doesnt work, and click on 'reset' (i hope thats the english term they used :)) .. or turn it off in that screen, and when its off, turn it on again

if you want to use your wireless connection, be sure its turned on in network connections

maybe your router doesnt allow the mac addres of your laptop ?

are you trying to connect to another computer from your laptop ? or are you trying to use the internet connection of that other computer ? or are you trying to connect to the network via a router ?

it did work when you had the lan cable connected ? but it doesnt now that you are trying to do it wireless ?