First of, this is not a no sync problem.
If you have lost sync the DSL light will flash in a slow steady pattern.
If you have a solid DSL light and no internet light this is a connectivity problem.
There are two types of connection you could have with Verizon, DHCP & PPPoE. With DHCP you authenticate with your MAC address. You are probably not DHCP since the MAC address in this case would come from the Westell 6100 which would not have changed. With PPPoE you authenticate by means of a username and a password. If for some reason the username and password in the modem do not match the ones you created during account setup you will lose your connection. When this happens the internet light will turn red and/or turn off.
If you lose power or reset the modem, this will happen.
If you know your Verizon Online Username and Password then follow these steps.
Open Internet Explorer
In the address bar type in; 192.168.1.1
When prompted for a username/password type in the following;
username : admin
password : password
Then a screen will come up saying enter administration name & password.
This screen is to change the username and password for the modem.
Type 'admin' in all three boxes and click change.
Then click on profile editor at the bottom of the screen.
You will again be prompted for a username & password, both will be admin (if you followed that instruction, otherwise use whatever you entered for the administration username&password).
Then click on new connection (at the bottom)
The connection name is My Connection, you can change this to anything.
The Account ID is your Verizon Online Username
The password is your Verizon password.
If you run into problems call Verizon Tech support, this is a very common problem that any tech support agent can walk you through in fairly short order.