It has played them in the past--no problem. I discovered this today when I tried to play a file called exam.avi. WMP came up and the sound was there but not the movie. I checked to see that under Options --> File Types tab, the avi box was checked. It was.(All file type boxes were checked.) Tried again to play the file (it was on a CD where I'd saved it). Again, sound only.
OK. I went to the site where I had originally obtained the file and again playing the file directly from the site I got sound only.
So I then re-downloaded and reinstalled WMP 9, went back to the site I'd gotten the file from and tried again to view it. But still I got only sound.
Has someone some ideas as to what I can do now?