I went to the https://wifi.xfinity.com/connect-devices.php site to try to download the xfinity wifi app for my computer, but when I do, the program that gets downloaded is a .mpi extension vs a .exe extension, so my computer can't open it the program to install the program. Any suggestions on what to do? Thanks
Did you mean an .MSI extension? Those are Windows Installer files (see https://www.google.com/search?q=msi+file), and the problem is probably that the file you are getting is empty ("Size: 0 bytes"). See http://forums.xfinity.com/t5/Your-Home-Network/Not-valid-package-installer/m-p/3016048#M269447 and replies.
Comcast thinks they fixed the problem. They didn't. I'm seeing this in Edge, IE, Firefox, and Chrome.