OK, from the IT dept's view now:
If he were one of my users he would not have the authority to create local users accounts, simply because of situations like this.
A simple question has got very convolluted, and confusing to some readers. The simple answer is - the laptop will be supported by the company's IT dept. who will talk the user through removing the tick from "Use a proxy server", and instruct him to turn off the cable modem, connect the latop, turn on the cable modem, wait a short time, then get the user to ping a known server (such as
www.yahoo.com), if all works fine he's done, if not further troubleshooting will take place.
As I say, if he were one of my users.