I downloaded a movie in the mpg format and one in the avi format.

QT says that it is missing software to open the mpg file. QT opens a movie window but says it can not play the avi file, that it is missing a compressor.

VLC opens a window that shows a Warning and then the window closes when I try to open the mpg file. VLC opens a window that is black but plays nothing with the avi file.