Loss of sound with video clips

The product is an Ixus55 (Powershot SD450). Although my Ixus video clips can play sound they are failing. This applies on all players (Windows Media, Real, Winamp or Canon's own ZoomBrowser software). It only applies to my Ixus; clips from other cameras are OK. It also applies only on my own computer (a Toshiba laptop); the Ixus clips are OK on other machines even copies taken from my computer. (A CD written on my laptop will work perfectly well without any adjustment on other computers but not on mine.) So the problem is specific to the combination of my computer and my camera.

I had some initial success when I tried alternative players. It is difficult to remember the exact sequence of events but the problem may be initiated by double-clicking a clip rather than opening the player and importing the clip. It is relevant to note that the problem applies to all the Ixus clips or none of them - once one fails they all follow suit and vice versa. I have also been able to restore sound by converting the avi files to mpeg with a downloaded converter but this severely compromises the picture quality.

I'm baffled. Has anyone any ideas?

Sounds like the problem may be with one of the "codecs" (coder/decoders) on your computer. You might go to Control Panel | Sounds and Audio Devices Properties | Hardware and try removing video codecs one at a time; they'll be reinstalled next time you try to play something that needs them. But this should get you a clean copy of the codec. I'm afraid I don't recall which codec is used for this, so I can't tell you to "go to this one, and that'll take care of it".

Thanks Jon. I tried that with no success. (Each time I deleted one of the video compression codecs it was automatically reinstalled when I closed the window so I tried viewing one of my files while the window was open. Hope I did it correctly.) I also tried disabling the audio compression codecs one by one, again with no success.