Are you able to ping your router? Assuming you are in Windows, open up a command line (Start -> Run -> "cmd") and try "ping 192.168.1.1" to see if you get anything back. One other thing to try from the command line is "ipconfig /all" - this will tell you if any of your connections are disabled. If so, re-enable them from the Windows Control Panel, depending on your version of Windows the option there is either "Network" or "Network Connections".
Have you used this router before with other PCs? If not, you may need to do router config as well. If you're like 90% of all home broadband users you are probably on some sort of DHCP/PPPoE setup. Read your router's manual to make sure it is signing you on correctly to your broadband service, and that it is set to work as a "DHCP server". You'll know this is working when, if you go back to the command line and do "ipconfig /all", your IP address will show up as 192.168.1.<x>, where x is a number between 2 and 255. (It won't be 1, remember 192.168.1.1 is your router)
Hope this helps,
-Adam in Philly