Problem with video on the monitor screen?

When I press for video display of any article, I find that a black screen in centre appears with a one centimeter dia circle moving. It revolves for say 5 - 10 seconds and video starts running to stop in just another 2 -3 seconds. Again that circle appears with dark background . It again revolves for the more or less same period followed by running of video from the point it stopped earlier. This process is continuously repeated till video gets completed. Can some one help please.