Click Start, then in the search field at the bottom type in "cmd" and hit enter. Type ipconfig and hit enter.
What's your default gateway? Should be 192.168.1.1 or 192.168.0.1. Type that into your internet address bar to log into your router. Your name/password should be admin/password, or just admin and blank. Depending on the router, it'll give you all kinds of info.