autofocus - What settings affect how the focus points are displayed for my 7D?

My Canon 7d is about 2 months old. I used it for a shoot in DC, and it just isn't behaving as expected. When I try to focus, I get little black boxes in the focus frame. They used to be black, with the focal area in a red box. I let my girlfriend use the camera for a few hours, and I can't figure out what she's changed. Do I need to reset to factory settings? Or does anyone have an idea of how to tun my focus squares back to red, and to make them selectable?