Time Warner has come out twice, and we've spent countless hours on the phone, for them to tell us every time we call, that we are working, and they can see which websites we are trying to access. But, it doesnt come through here. Everything says unable to access... This is getting ever so frustrating
Verify you are getting an IP address.
Ping your Router (if you have one in place).
-If you have a router, log into the router to verify you are getting a public IP address.
If you do not have a router, verify your computer is getting the public IP address. Try to ping a website and/or the DNS servers.
If this doesn't work, your ISP may be locking your MAC address. This is based on the fact that you state only a certain USB NIC works.
Sounds like the issue with the router, have you replaced it with the same model each time? How many computers are you attaching to it? If more than a few, is the router model made for home or business use?
Have you by-passed your switch and connected right to the router to see if things work that way? Is the switch a "smart" one that you can configure each port? You may have different subnets setup on the system. Does ipconfig on the computers show the correct IP info for your network on all the systems?