Intermittent Wifi

I have a Ubee DVW326 Modem/Router. Starting a bout 3 weeks ago, the wifi intermittently stops working (i.e. will not respond to pings or connection attempts). I notice that whenever this happens, the Wifi light is solid on. When the Wifi is working, the Wifi light flickers normally. Also, the unit occasionally seems to spontaneously reset. Could this be interference? Or is it indication of a malfunction?