After doing some research, bought the Motorola SB6121 cable modem to use with my time warner service. Installation crew came to set up the cable line, etc, and used my laptop to activate the service (connecting laptop to cable modem via cat5).
Bought the Netgear WNDR3300 to use as a wireless router for my home network. After connecting the router and modem, I kept encountering the same issue: wireless bars with a yellow triangle (windows) on the network connectivity display. After mucking about in the configuration options for the Netgear router, I did some google browsing to find this thread:
What I didn’t find in any instruction is that the cable modem needs to power cycle, and when it does that, it changes what device gets provided service. The cable modem was left on the whole time while I was power cycling the Netgear router. The other laptop I used to test connectivity wouldn’t get signal at all either.