換電腦之後有些下載下來的mov檔案都不能看 只有聲音沒有影像

要不然就是開啟一下就當掉了 有時候還會出現這樣警告

you may experience problems playing video track in harry potter and the prizoner of azkaban? because the required compressor could not be found would you like to close the movie or continue?

這些字是什麼意思啊 請各位幫我解答吧 多謝災