Trouble connecting netgear wireless router to rca modem DCM425

First try connection the Yellow ethernet cable from the rca modem to your computer's network connection. If you get a connection this way, then your modem will work with a ethernet cable. If not, then call Comcast for help. The modem ethernet out to computer port must be connected to the wan line of the router. Then you can connect an ethernet cable from your computer network connection to one of the 4 ports of the router. For wireless connections you must set up the router and wireless adaptor with the same settings to connect. Follow the routers directions.
Good Luck

YOU CAN ONLY CONNECT EACH DEVISE WITH EITHER USB OR ETHERNET BUT NOT BOTH.