I have a home network at my old house, on DSL and using a Linksys 4port router. We had another router as well, so we had three machines plugged directly into the router, and then another small 5port switch plugged into it and several more computers plugged into that switch. It worked perfectly. But now, we are moving. Now we have cable internet (Roadrunner) and I called Linksys before we moved. They said that the router would work with our new internet, great. Now I have the cable modem plugged in, internet is on. Our house is wired for Cable internet, with a wall plug for CAT5 in every room with the ends of the wires in the same room as the cable internet. I took a computer over to our new place, plugged it into the wall then plugged the other end into the cable modem directly without the router. Works perfectly.(I am on that now) But if I plug CAT5 into the cable modem and into the Linksys 4port router, then plug the computer into the wall and the other end into the place where the systems are supposed to be on, a problem occurs. I can ping and access the router perfectly, but the internet does NOT work. I tried plugged the cable modem into every possible place on the Linksys, with no luck. Anyone know what's wrong?

Reset the router to its default settings and try it again.

If you have the CD that came with your router. insert into the CD drive. Click on set up router. Follow directions. It should set the router up automatically. The modem is probably trying to use the mac address on the pc card that the the cable was set up on. You can try cloning the pc card mac address to the modem, if it doesn't work you can always reset the router.