
to CF
First question - have you rebooted (unplugged) the CM during this process? Whenever you change devices on the modem you need to reboot.
Second - Is the router a 'Cable Router' - as opposed to an ADSL router? What model of router?
Third - have you plugged the CM cable into the 'WAN' port on the router - most Cable Routers will have one port for the WAN (aka upload) and four ports for the local devices.
That'll do for starters.
HTH