My pc has room for one ethernet cable and its already taken to a router box. i have no idea what its for but now there seems to be nowhere to hook up my 360. i want to hook up for xbox live and netflix. please help me. i do not speak 1 word of geek

try to check the the network cable.there is something wrong in your cable.maybe wrong setting of wires.but you said you got wireless router right.why go on wireless..much better you buy a wireless USB connector.less maintenance.if you prepared wired..this is the setting of pins of network cable.8 pins each RJ45 both ends. 1.stripe orange 2.orange
3.stripe green 4.blue 5.stripe blue 6.green 7.stripe brown 8.brown

Base from the description of your problem it seems that the Ethernet port on your router is already bad and got busted and causing this type of problem and since you have the router for a long while already, this router needs a replacement already since the problem is not a firmware issue but a hardware issue on its Ethernet port.

Take the ethernet cable which is going from your Warner cable modem to your computer, and run it from your cable modem to the input connection of your router. Then take a second ethernet cable and run it from the router (ports 1, 2,3 or 4) to your computer. Log into your router's setup page (see your instruction manual), and set up all the passwords and wireless settings. Please read the instructions for specifics of your particular router.

Plug ethernet cable from the cable modem into the router input and plug vonage ethernet cable into the router ethernet port.

make sure that your cables r connected correctly, just swap them around internet and ethernet on the back of your router. Also make sure u run your software wizard that came with the router. also the cable that is running from the back of your computer should connect into router internet port then your ethernet cable should run from router to dsl box

If you are connecting to either broadband cable or dsl you pretty much have the same steps. First hook up the modem (dsl or cable) with its own power cable and its own internet connection coming in (dsl will be a usually green phone cable)(cable will be a coaxial line that the cable guy already hooked up). Next get the netgear router and plug in its power cable somewhere near the modem, then plug in a preferably crossover ethernet cable to the uplink connection on the back of the netgear, should be on the same side as where the power cable went in. (and yes you can probably use a straight ethernet cable as well) Plug the other end of the ethernet cable into the only location it will go on the modem, both boxes should already be setup for use, if for any reason they do not work just pull the power on them both at the same time and wait a minute or two and replug them back in for power resets.

First try connection the Yellow ethernet cable from the rca modem to your computer's network connection. If you get a connection this way, then your modem will work with a ethernet cable. If not, then call Comcast for help. The modem ethernet out to computer port must be connected to the wan line of the router. Then you can connect an ethernet cable from your computer network connection to one of the 4 ports of the router. For wireless connections you must set up the router and wireless adaptor with the same settings to connect. Follow the routers directions.
Good Luck

Do a ipconfig at the command prompt and see if you are being assigned a ip from the modem. If not try rebooting the modem with the ethernet connected to modem and computer. then do ipconfig again to see if not getting internet ip, your card or modem eternet is bad. put in a new one and try again.

run the modem to the router with Ethernet cable and then use one of the other Ethernet ports on the router and another Ethernet cable to connect desktop

You can't get an IP address on the Xbox that way. You need to get an IP address from a device that works as a DHCP server such as a residential router. Connecting the Xbox to the PC will do nothing for you.