I am trying to follow you comments about the setup.
I do not know what the Multiplexing and VPI/VCI should be, so if your old one worked, it is probably correct.
I do not see a place to put User Name and Password, maybe on the setup wizard.
IP Settings should be Automatically Obtain IP Address, and it will come from the ISP. When the Modem is connected, this info should be filled in.
Host Name and Domain Name, I suppose are given by the ISP?
I get a little confused here because you are doing a ADSL setup, but the next page (web access) shows an Ethernet mode setup, which you would use with a Cable Modem... On that same page is the Network Setup, so I will assume this is for your LAN and not related to the WAN setup.
Then you get into the Wireless Security settings. Since I do not remember if you are connecting wirelessly, are these necessary?
I can't read the images for the setup Wizard, but you have checked to make sure the info you entered is showing in on the Web access pages?
Open a command window and type ipconfig /all to check if the IP addresses are as you would think. If you are showing a 269.xxxx address, then your network adapter is not recognizing a Home network and is assigning a Windows default address.
If you like, hold shift and right click the desktop, then select "Open Command Window Here". Type the following and use whatever name for your file you want..
ipconfig /all > Myconfig.txt
You can edit it as you like, and add it to your response, or attach using the paperclip. Maybe it will show something.
As far as the firewall is concerned, try turning it off, but they normally don't stop access.
Your comment about not seeing any WAN IP address or DNS address, probably means your ISP is not assigning you an address for some reason. It should be doing that, and I assume the old unit was set the same way.