Thanks for your reply. Both computers are connected via the built-in router in the modem. And both are connected via DSL cable rather than USB. The funny thing is that my old setup (Starsmart Modem and D-Link Router) worked just fine for both computers. I replaced them due to a problem in the modem which slowed my connection down significantly.
Anyhow - after working with Dell some more they determined that I couldn't flush the cache and that was the problem. I ended up re-formatting and loading the OS and that fixed the problem.
I still don't understand why it worked fine with the other router and why this software problem showed up but I guess it's magic. They couldn't explain it to me either (India Techs) so I guess I'll just be in the dark.
anyhow, it's working now.