Comcast told me last night that my modem is in a "walled garden."
My connection was working fine until, about a week ago, I uninstalled some old Norton anti-virus software through the control panel add/remove programs. This turned out to be a mistake, and for the next few days I couldn't renew my IP address. Comcast technicians came to my house twice, and ultimately threw their hands up in the air and said it was my computer (although they had no idea why).
I reinstalled the old virus software last night, and instantly got an IP address. But, the only page I can access is the Comcast page telling me to download the software. I download the software, go through the registration process, and get an error telling me to call Comcast.
And around we go...
I'm not getting anywhere with people over the phone...they just keep telling me that they can't get the problem worked out, and I should call back in a few hours or the next day.
> I reinstalled the old virus software last night, and instantly got
> an IP address. But, the only page I can access is the Comcast
> page telling me to download the software. I download the
> software, go through the registration process, and get an
> error telling me to call Comcast.
I had the same exact problem a month ago, except it happened for no good reason (eg. one day it worked, the next I got the registration screen... No changes made on my end...).
Called Comcast and the tech found that my modem had become unprovisioned. Evidentally there is some protected file on the modem which states whether or not it is provisioned, and sometimes things happen to that file.
Long story short, the tech re-provisioned my modem, reset it, had me reboot my PC, and I was back in business in about 10 minutes.
Only other advice is if you have a router, take it out of the loop. Turn off the modem, turn off your PC, connect the modem directly to your PC, turn the modem back on, boot the PC, then call Comcast. After you're done with the tech, you can put things back to the way they were. Just be sure to turn off your modem while moving it from the PC to the router.
PS - From when it happened to me...