Signal from router, but no internet. *Help Please*

I recently moved my room to a new part of my house (it's quite large). In my new room, I no longer get wireless signal from the original router. I spent around 100 dollars to upgrade not only the router, but also the adapter, both to Wireless N. This didn't really help. There are just too many walls to go through, and a long distance.

However, the "main" cable box/modem (from Timer Warner Cable, it supplies cable TV, internet, and digital phone services) is located on the side of the house I'm now living on. There is a cord that runs from this, underground, to the other end of the home that supplies the "main computer" its internet, also where the router is. I decided to try hooking up the old wireless router up to this modem box via ethernet cord. I was happy to find I get "excellent" signal strength from this router. The security is still there, and the network name is the same as it was before replacing it.

However..

When I try to access internet services, nothing works. Pages don't load, etc. It doesn't give the famous "limited or no connectivity" message. It just shows it is fully connected, strong signal. Can anyone offer some advice or an explanation of why it's not working?

These are some of my thoughts, most might be wrong, I honestly don't know:
- perhaps you need a wireless router connected to a computer to work properly?
- perhaps this main cable box which supplies both cable TV service and internet service doesn't supply internet when connected directly to it? (I would think it should!)


Tonight I'm going to plug a laptop directly into this modem box with an ethernet cord and see if I can get internet service. I would really like to use wireless though to provide internet to both a laptop and a desktop though.

Any tips/advice/suggestions/etc would be GREATLY appreciated!