When i first had my nokia 5530 i put in it a memorycard that was in my old phone so everything was good but when i video recorded something when i then watched what i recorded the first video clips worked fine but the last videoclip the sound of it was coming and going skipping so i turned the mobile off and removed the memory card then i put it for the other time and turned on my mobile then the all my videoclips where working properly why??