I'm not sure if I'm understanding the thread correctly, but when I
called Comcast, they said that they used the MAC address from the
modem, I gave them the one from the new modem, and everything seemed to
be fine.
I may have spoken too soon about the problem being solved. I now have
2 ethernet ports - the one built into the motherboard and the free card
from Comcast that I added (which I'd like to remove). I've had
inconsistent trouble when hooked up to the built-in port with Windows
flashing back and forth between the messages that a network cable has
been unplugged and then that it is connected. During this
"flickering," my LAN connection status shows that it is connected, but
I cannot pull up anything on the web. If I then move the cable over to
the added port on the PCI card, everything is fine and I can surf the
web. I was concerned that it was a problem with the first port, but
then I did have a couple brief instances of the second port doing the
same thing. So I thought that perhaps it was a problem with Comcast's
server, but they deny that there are any current problems. Any
insight?