Annoying Lines in the Videos???

hey all, my problem is when i play a video (using real player or media player) in full screen, there is columns of horizontal lines in both sides of the movies. the middle part is fine. initially, the video plays fine for about 5 seconds then the lines come out.

ive re-installed all the codecs and some new ones but the lines are still there. strangely, when i play them using winamp, there is no lines but the video plays very slowly in full screen mode.

anyone know of a solution? thanks.

nevermind... i just unistalled some codecs and the problem is gone for now.