I have a cisco linksys wrt54g2 v1 that I have hooked up to my verizon dsl modem. My computer says I am connected but it wont let me get on the internet. If I plug the ethernet cable from the modem to my computer it works though.

Connect your computer directly to the Internet modem and make sure that you have Internet access directly from the modem.
If that is working properly then connect the modem to the Internet port on the router. Connect the computer to port 1 on the router.
Reset the router and configure it manually.

Here is link which will help you troubleshoot Cisco Valet M10 or M20 router

Most modern DSL modems operate as a NAT. If you plug directly into the modem and get an IP address that starts with 192.168, the modem is the NAT. Instead of connecting the modem to the WAN port on the router, connect it to one of the LAN ports.

To see what your IP address is, assuming Windows, open a command window. At the command prompt, type "ipconfig" (without the quotes) and hit Enter. It'll return your computer's IP address.

The simplest way to test this is to simply connect the modem to the #1 LAN port, using the supplied ethernet cable. Power the modem and router down. Fire up the modem. When it's active, fire up the router. Now connect and see what happens.

This is the direct link to the Firmware update simply scroll down and under Firmware click download.
http://homesupport.cisco.com/en-us/wireless/lbc/WRT54G
copy and paste into address bar.

For Windows XP and Vista:

http://homedownloads.cisco.com/downloads/setupwizard/1224638318022/WRT54G2_USCAN.4.9.9020.0-ship-Stable.zip

For Mac:

http://homedownloads.cisco.com/downloads/setupwizard/1224638318015/SetupWizardMac_WRT54G2v1_4_1_.9.8113.1_US_CA.zip

You can download it from here,

http://homesupport.cisco.com/en-us/wireless/lbc/WRT54G2

Select XP, Vista Setup wizard download.

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Are you trying to install the router.
You can do it manually without the CD.
MAke sure that your computer is able to go online through the modem.
If your computer is able to go online through the modem
Then you need to connect the computer to the router ad the modem to the router.
open the set up page of the router and change the settings of the router according to the ISP.
Click Here for step by step by instructions

You could try updateing the Firmware

I think, you can get the installer in the linksys website.

To connect to the router wirelessly using a Windows XP, right click on the wireless network connection icon on the lower right corner of the screen and choose view available wireless networks. Select your existing network and click on the connect button. If you are using Vista, go to network and sharing center of your control panel then select connect to a network. If you still having problems, please provide details of the problem like your Internet service provider and if there are already other computers online with your WRT54G2.