Here's a driver-free, software-free solution.
Turn your cable-modem (or DSL-modem) off.
Turn your Netopia off.
Ethernet--port on cable-modem <-- cable --> WAN port on Netopia.
One LAN port on Netopia <-- cable --> network-port on your computer.
Turn the cable-modem on, and wait until its lamps settle-down to a repeating pattern.
Turn the Netopia open, and wait until its lamps settle-down to a repeating pattern.
Restart your computer.
Look for output like: Default Gateway ... 192.168.123.456
Start Internet Explorer
(or whatever numbers you see)
Login to the web-server running "inside" the Netopia.
Click to run the "Wireless Networking Setup Wizard".
Enter an SSID of your choice.
Select the 'WPA' level of encryption.
Enter a network-password of your choice.
Restart the router (if it did not automatically restart).
Disconnect the Ethernet cable from your computer's network-port.
Click "View Available Wireless Networks".
Click the SSID of your new network.
Enter the password, when prompted.
Voila! You have a wireless connection to the internet.