I recently buy a samsung full 23 hd monitor. when computer is booting the screen is sheking.when ever black screen( wallpaper, game starting screen) appeard then this problem shown. and there are some lines are also appear in black screen. this problem is only appear only in black screens not others. this is show minor that you recognised iy when you closely look at it. is it monitor or hdmi cable problem. Please help. Thanks in advance.