Media Center Screen Flicker when using online content

My problem is this. .. I open media center, go to the online content section,
and click on one of the available stations (say Jazz). When the new window
opens I get occassional screen flicker. In addition, everytime I click on
the little blue box in the left hand corner of the screen as it enlarges and
moves to the center of the screen (to provide options such as visualizations
or shuffle), the screen flickers about 5 or six times.