wireless router adapter

Please move this as needed. I was using my primary tower and suddenly I lost my net connection. It turned out to be my router died, some of the indicators went out. I went wired, removed the router. I then set up my secondary for finishing. I decided to go wireless. I added a MOTOROLA 850. I installed a ENCORE wireless card and using the cd for installing the software. It works perfectly with and without the ethernet cable and with connection wired disabled as it should. The issue is that my HOME page in all 4 browsers has changed to a SIGN ON page for XFINITY/COMCAST provider. I could not revert to my previous home pages using the usual techniques. The COMCAST page refused to leave. I DO NOT HAVE COMCAST service in my town. I have CABLEVISION of CT. THAT page never appeared on its own. With the COMCAST page displayed the address bar is disabled as well. I changed the card to a usb adapter. Same issue. The only way to cure this disease was to remove both card and usb and revert to wired on board nic. This tower apparently cannot be wireless until this issue is solved. I set up the identical tower using the same card, although different router, for a friend and her system is fine. I have used this same combination in the past for myself and different combinations as well and never had an issue. What IS the issue here and what is the solution? The configuration screen ALSO does NOT open so I do not know what router if not mine the wireless is connected to. My provider cannot help. Solutions please. I do not have another tower to try, although I am sure the issue is not in the tower. I also do not have another router to try. The router works fine in all 4 ports. That is not the issue either. I am completley stumped.