I did look at a similar question with responses that did not solve the problem for me. I have a D-Link switch I used for several computers when I had DSL through Verizon, I switched to Comcast which uses a MOTOROLA SBV5220 CABLE MODEM/VOIP . I cannot get it to work. I have re-set the modem and the switch. It will work with only one computer at a time Can you please tell me specifically what to do, what to buy and how to set it up. thanks.