I know that this sounds like a dummy thing to do and if you call the cable compan they will tell you the same thing....
Unplug your cable/DSL for at least 5 minuets and unplug your router for 5 min.... then plug in your cable/dsl wait for full boot up, and then after that then plug in the router. See if anything comes up.
If that doesn't work unplug your cable/dsl... Just do a hard reset on your router. There is a reset button in the back of the router tha reqires a bobby pin, hold forat least 20 seconds or until you see the lights flash indicating there has been a reset.... once it does a full reset, then unplug the router, plug the cable/dsl back in and once the cable boots up, then plug the router back in.