Not connected to internet

Your Internet service provider is comcast cable company.
You need to open the setup page of the router and change the Internet connection settings manually.

Connect the computer to the router and modem to the router.
Open the setup page of the router using 192.168.1.1
Click on MAC address clone. Enable it and click save settings.
Power cycle the router and your main computer will be online.
Then you can change the wireless settings manually.

Click Linksys router setup steps

If I am not wrong then this number ( CGN91F5G2439 ) is serial number of WRT54GS v6 router.
You can setup Linksys WRT54GS router without CD. Connect your computer to the modem and make sure that modem is getting active Internet.
Connect the computer to the router and modem to the router. OPen the setup page of the router and change the Internet connection settings of the router.

To secure your wireless network from unauthorized access,please click on this link and follow my instructions :- http://www.fixya.com/support/r3559128-wireless_router_security

LinkSys Wireless-G WRT54G 2.4 GHz Broadband Router with 4-Port Switch:

Go to LinkSys Login. Resetting the Router will erase all of your settings (WEP Encryption, Wireless and LAN settings, etc.) and replace them with the factory defaults.
There are two ways to reset the Router's factory defaults:

• Press the Reset Button for approximately 10 seconds
• Restore the Factory Defaults from the Administration tab in the Router's Web-Based Utility. (Go to LinkSys Login.)

The Internet port is where you will connect your broadband Internet connection.

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With the help of your Gateway router, you can share your broadband internet connection with multiple wired and wireless devices. Backed by Gateway's online customer support, any issues with you network and router should be resolved promptly.

You can still use your existing Linksys router with your cable modem. In fact the router your have is designed to work with DSL/Cable Broadband connections.

1. Make sure to properly connec the devices in your network. Modem will be connected to the Internet port of the router. Then, laptop will be connected to one of the 4 Ethernet ports of the router. For initial setup of your router with modem, you need to hardwire laptop to the router.
2. Press and hold reset at the back of the router for about 15 seconds.
3. After 15 seconds turn off the router and then turn off the modem. Wait for a minute.
4. Power on modem and wait for the lights to be ready.
5. When modem lights are on, turn on router.
6. There should be 4 lights on. Power should be steady green. Internet, WLAN and Ethernet port.
7. Checked if you have Internet connectivity on your laptop while it is wired to the router.
8. If Internet is working, disconnect laptop from wired connection to the router and check available wireless network that laptop can detect.
9. The default wireless network name that the Linksys router broadcasts is "linksys". Connect to it which is an unsecured wireless network.
10. Once you are successfully connected, check Internet.

Hope this helps!

Try running this MS router test:
http://www.microsoft.com/windows/using/tools/igd/default.mspx

Hi,
I am having the same problem with the WRT54XG4 but i discovered that if you disconect the internet port of your router and leave the ethernet port conected to your computer. You can access to the router and you can upgraded.

Hope it help you

bye

reset router

From you DSL modem or broadband router, what is the next device connected?