how can a wireless network display a window on my desktop with no browser open
Sometimes when I start my computer, instead of my home wireless network, the computer will join the local comcast network. They are then able to display a box on my desktop asking me to join xfinity. As I do not have a browser open at this point, I have no control over anything they might load to my computer. Any ideas?
Macbook Air 11 inch running Maverick