Odd, just for giggles try using https instead of http, and then type using :80 to designate port 80 afterwards (192.168.1.2:80). You could also try a port scan of the IP, see if any ports are open besides 80. Maybe the default web port got switched. Could give 8080 a shot as well.
Beyond that, I can't think of much. Clearing your browser cache, maybe using a different browser or a different host to access it. You may have to resort to a hard reset (holding the reset button for 10 seconds +) Should restore the router to factory settings, which may be 192.168.1.1, so it could have a conflict by default if your switch is set to 192.168.1.1. Best of luck to ya from here - Sub