This solution that worked for me and i’m using Windows 7:
Uninstall Quicktime 7.7.2 and reinstall the older version 7.7.1, here’s the link for it:
THanks byutrumpet!! That solution worked, but I was alittle affraid of the site you recommended to download from... I'm not familar with that one. I stuck with the apple site and went to an even older version, but it fixed my problem...
Here is the site i used.
I unistalled current version 7.2.2 and downloaded "QUicktime for windows 7.6" from above site... Quicktime now plays the video w/sound for the iso 6 videos from my iphone 4s....