Xfinity (Comcast) Wireless Router Connection Problem

I recently picked up a modem/router combo from Comcast to set up a wireless network at my home. I was able to connect to the router and secure the connection using the "Quick Start Guide" provided, but I've encountered an issue connecting to anything other than the "Wireless Gateway" used to setup the network.

Airport shows I am connected to the network established, but attempting to load a website yields nothing but a long thinking cycle before stating "You are not connected to the Internet." Even the gateway shows my machine as connected.

I'm a total noob to this, so any info on what may be causing this would be much appreciated. And if anyone has a resolution to my problem, that would be even more awesome. If additional information is needed, let me know.

Thanks in advance.

MacBook Pro
Mac OS X 10.6.8

When you set up the router's Wifi what encryption did you choose? WEP? WPA? WPA2? Did you make a key? Are you entering the key correctly?

If you hook up an ethernet cable directly to the Mac from the router, does it work then?

I forget which encryption was chosen, but I'll confirm and get back to you. I did create a key and am entering it correctly (I used it to connect to the wireless network created).

I didn't even think to try a direct connect between the router and Mac via ethernet cable. I think my brain was fried trying to get the wireless working. I'll give that a shot and let you know what I find.

Thanks!

Well, after connecting the modem directly to my Mac via ethernet, I found I still couldn't get on the Internet. I gave Comcast a call, described the problem, and it turned out the modem was "locked out." I'm in good shape now.

Thanks dtravis7 for the attempt to help me out.