I have a 3 yr old MacBook with Snow Leopard and am finding I am having trouble viewing videos. .... tv shows .... youtube.... etc. Some times they work fine other times the voice breaks up and you can't understand what is being said. Also the picture will pixilate and freeze...may hear sound and picture freezes... I don't know what could be the cause... I checked the upload and download speed of the Internet... sometimes it was down but other times it was coming in at a fast speed and it still happened. Any ideas?