ATT uverse gateway will not recognize my computer?

I have att uverse and all of a sudden I cannot get onto the internet on my wired computer. The gateway will not recognize the computer. Any ideas on what I can do?|||Does your computer show that the local area connection is currently connected? If it does not, then try unplugging your ethernet cable that is connected from the Gateway to the computer. After that reconnect the cable again, but this time on the RG side, plug the ethernet cable into a different slot, either 1, 2, 3, or 4, whichever did not have your computers ethernet cable to begin with. You going to want to look for a light close to where you plug the ethernet cable into the RG, also there should be one on the back of the computer tower also. If there is no light then you may want to try another ethernet cable. Now I know that U-Verse uses Pluglink devices for computers that are not close to the Gateway and that they do not give wireless adapters to. If your using those then there will be one connected to the Gateway and one on the Computer Tower. With these you need to make sure that the 3 lights on the devices are lite. If not then turn off the computer, unplug both Pluglinks, and then reconnect the one on the Gateway and then the towers. Power the computer up and check for connection. Let me know if anything helps.