My Linksys router WRT54G isn't working!!!

Hello

I have a linksys router WRT54G connected to a modem supplied to me by Time Warner Cable. Just last night, for some reason my internet stopped working. After calling Time Warner Cable internet support, I found out that the modem is working. If I connect my laptop (Dell model which is running on Windows 7) directly via cable to the modem, I can connect to the internet. BUT if I connect my modem to the router, and then connect my laptop via cable or wireless to the router, I can't connect to the internet. When I open up my network window on the computer, I see that my laptop is connected to the router and the router is connected to the internet but I can't connect to the internet. I tried calling linksys customer service and my insurance ran out so yea ... On the laptop, I ran a troubleshooting program and it gave me an error stating that it failed to connect to the DNS server and I should contact the internet provider. Time Warner Cable told me that if connected to the modem directly, I could access the internet indicating that there's an error in the router. With my warranty expired can someone please help me solve this problem.

Thanks in advance