Have you tried checking your Firewall?
It could also be possible that your router is blocking the ports necessary to access your games. If you know how to port forward then you can look up the ports for your specific game server(s) and port forward them. It is very easy to port forward, merely look up how to do it with your router name.
If all else fails, call up your ISP and ask them for a new IP and have them come out and take a look. You might be able to change your IP your self. I was able to with "Linksys Smart Wifi"