I will try anything today. After removing the modem yesterday and trying another one, I reinstalled the Westell.
Please elaborate on exactly how you "reinstalled the Westell".
If it is possible, I'd like you to do the following. If there is a problem/question at any point, just stop and ask for advice. None of this changes anything on your router.
In your browser, type the router's address: http://192.168.1.1 and press Enter.
You should see a panel to log in to the router. Try the following for "User" and "Password".
User: admin Password: password <<< This is probably the default.
admin admin
admin (blank)
(blank) admin
If you can't get logged in, it might not be advisable to try adding another router - unless you got one that is a combination DSL modem/router and you're intending to get rid of the A90.
Assuming you get logged in:
On the "Home" panel:
1. Highlight the Security tab and select Security Level, and write down the security level.
2. Highlight the Security tab and select Security Log, and see if there is anything interesting.
3. Highlight the Advanced tab, select LAN and then the DHCP pulldown. Write down all of the information on that panel.
4. Highlight the Advanced tab, select Diagnostics, then the System Status Tables, then LAN Devices. Write down all of the information on that panel. Hopefully, you will be able to tell which one is the WLIP. Be very careful to get the "MAC Address" recorded correctly.
Now you can log out, and post information on what you saw.