This might help

First go to Device Manager and see if there is a "Network Adapters" in the list, If so is there an eathernet adapter listed, it might be called a local area connection or broadband connection, if so highlight it and select Properties in the Actions dropdown. It should say "This device is working properly". if so then go to Network Connections in the Start button menu. There should be an icon called Local area connection. double click it. The connection should be useing "Client for Microsoft Networks and Internet Protocol (TCP/IP)". if so plug an eathernet cable into your DLS modem and the eathernet connecter on the laptop. there should be a little light beside the connector that comes on when you plug it in. If all this is so than it should work. Modem jack has 2 or 4 wires in it, eathernet has 8 don't connect modem connector to DSL modem. Also you might go to Dells support website to get drivers and also documentation for the machine.