The secret is likely in the MAC address of your computer.
Most of these systems log the MAC address of your machine when you register. They load these MAC addresses into a security file, which locks out any machine that is not registered, as the MAC address for that machine is not in the log file.
Solution - Hardwire your new wireless router to your computer, and go through the setup program. They always should start with setting up the LAN connection to the router from the computer, and then move on to setting up the WAN link from the router to the network. This is where you hit the roadblock, because the MAC address of your router does not match the one on file, and the link goes dead. During the setup process for the router, you should encounter a step where it asks you about 'cloning' the MAC address of your computer onto the router. What this does is change the MAC address that the router returns when asked, to that of your computer. So the network thinks it is still talking to the computer, when it is actually the router. Do all of this hard wired. Once you get the network talking to the computer, through the router. You can move on to setting up the wireless features, and unplugging the hard wire between the router and the computer.
been there - done that