Hello there what Operating System is this computer working on please Windows 7 etc?Can you see the name of your new wireless system showing in the list of available wifi networks please?
Hello so this computer is Windows 10 and you can see your mi-fi and sometimes the Comcast listed in the available networks please?
To view the available networks in Windows 10, please single left click the little TV looking icon on the bottom right of your computer screenYou should see your Comcast system listed and if you click it, you can join the system. You will need to enter the password ***** the box that appears to be able to join the system. The password ***** most probably be written on a label on the bottom of the wireless system itself. It will say WPA key or network key or some such.