New Dimension 4600 Network set up as follows:

Cable Modem -- Router -- Switch -- Computer 1

                                                       -- Computer 2

                                       -- Switch -- Computer 3

                                                      New Dell Computer

Computers 1, 2 and 3 access the internet just fine. Thus, the cable modem, router and switches are working. I can't get the new computer to access the internet. It seems to recognize the LAN because a little popup comes up on the bottom right of the screen when I turn off the switch.

Any help would be appreciated.