I just bought a new cable modem, a Motorola Surfboard off Ebay. It is new, at least it looks new. I called Comcast and gave them the serial number and mac address but I cannot connect to the internet (I am at work). The modem is on line and connected and shows activity and comcast was able to reset it from their site. I am using a Linksys router and did not change any config settings since I didn't have to enter anything for the old modem (an RCA) into the router. Comcast is stumped, they did say that something wierd was in my account and asked if I had any problems before and I said no. Do I have a bum modem or is there something I need to change in the router? I even tried the modem connected directly to my Mac via ethernet but still nothing. Comcast wanted me to leave the modem unplugged for a few hours to "reset it". Any help would be great.