Guide defaults to category choices. Why?

When I open the guide, the bottom half of the screen shows various
categories (All on now, Movies, Kids, etc.). I have to make one of these
choices before I can scroll through the guide.

It never used to work like this. I assume I changed a setting somewhere, but
I can't find where. Any advice would be much appreciated.

 

If you press the guide button when you are in the guide, you will see these
categories. If you are pressing the guide button only once, you may be have
an issue with the remote or the sensor. Since you have not made any changes,
it would suspect the following...

1) You batteries in you remote are weak
2) You are getting some interference around your IR sensors (Flourescent
Lights, Sunlight, etc)
3) You have some keyboard software that in adding and extra keystroke
4) You may need to install the IR Sensor update from Windows Update