Sorry for the delay...
The connection is not working because of a conflict between the Linksys and the Westell modem. They both share the same network/IP address, so they won't communicate when connected together. You can change the address of the Linksys to make this work, then everything will be online. Here is how to do it:
Power off the modem and pc. Connect the pc with an ethernet cable to one of the 4 ethernet ports on the back of the router. The modem should not be connected at this point. Disconnect it if it is currently connected.
With power still on to the router, press and hold the reset button on the back of the router with a pen for 15 seconds, then release. Power off the router.
Wait one minute, then power on the router. Wait one more and power on the pc. Open Internet Explorer and enter this address:
A login screen will appear - use this login:
(There is no username - leave it blank.)
You should now be inside the setup of the router.
Click Wireless - change the configuration mode to Manual, then save the settings. Save the settings at the bottom of the page.
Change the network name (SSID) to something different - this will be the name of your network. Save the settings at the bottom of the page.
Click Wireless Security, just below Wireless. Change the security mode to WPA2-Personal. A box labeled pre-shared key/passphrase will appear - this is your wireless password. Enter anything you would like, just make sure it is at least 8 characters in length. Save the settings.
Now, the important part - click the Setup tab - find the Local IP Address and change it from 192.168.1.1 to 192.168.5.1. Save the settings and power off the pc and router.
Reconnect the modem, then power it on - wait 60 seconds.
Power on the router - wait 60 seconds
Power on the pc
You should be back online and able to connect wirelessly. If you have questions how to do this part, please ask...