I read lots of posts about DELL Latitude WinXP laptops (including model 630) Ethernet cable connection problems. When I first had machine, I too thought I had a bad cable or connector, but I later learned that was not the problem.

If the machine is started with the wireless modem turned on AND with the Ethernet cable disconnected, the power to the Network Card is Shut Off. That (wireless modem turned on AND with the Ethernet cable disconnected) is the configuration I frequently accidentally start with when returning from a trip. However, as soon as I realize I have no Internet connection, I remember to plug in the Ethernet cable and turn off the wireless. My problem then is how to get the machine to recognize that the network cable is connected.

My ONLY reliable solution to date is to restart the machine, but I would hope there would be a more direct and less time consuming approach. In the past, I think I found a "repair network connection" menu item, but I've lost the path to it.

Can anyone offer a suggestion?

repair network connection,can be found by right clicking on the network icon down by the clock ,chose repair ,if thats not there ,then in network connections ,in control panel ,and right click on the icon for the conection ,chose repair

Do you have the Dell Quickset Application installed? There is a setting in there to enable/disable the network adapter(s) depending on your power settings. Very tricky if you don't know about it!