i have a cox cable connection on my vizio hd tv screen i attached the cable to the wall and to the tv then went to tv and scanned for channels... well it takes a while to scan but doesn't find any channel's .. does anyone know if i have to change the in put to TV,AV1,AV2,COMP,RGB,HDMI1,HDMI2 or the source to cable or antenna (it seems pretty obvious but this stuff seems so confusing i dont even know where to start anymore) o and im pretty sure its not an hd cable