A650is Video Error Messages

Hi All

I have a Canon A650is. Up until recently, every time I used it to shoot a video it would transfer fine to my computer in AVI format. I could play the videos with Windows Media Player and I could edit them with Canon Zoom Browser. So far so good.

One day recently I noticed that the icon of a video I had just shot and transferred to the PC had changed. Instead of the thumbnail consisting of a still from the video, it had an AVI logo and would not play in Windows Media Player. This is the same for all the videos I have shot since this point, although they can still be uploaded and played normally in YouTube. Obviously my first thought was a problem with Windows Media Player, so I reinstalled it to no avail. And neither can the videos be edited in either Zoom Browser or Movavi Video Converter, suggesting that the problem is with them and not what I am trying to play them with. I haven't altered any of the settings onthe camera.

Any ideas what might have happened?

Thanks

Mark