The only other factor I can think of is that these laptops use docking stations in the office and don't use the docking stations when users are on the road. There are two hardware profiles set up on each machine: docked and undocked. This has been a very aggravating problem. Dell Tech Support has not been able to help with this issue.
My suggestion is to make sure that you've installed DNS. While Windows 2000 seems to work OK with just WINS, Windows XP hangs while looking for DNS.
This was first published in February 2003