Barb, the other thing I was going to have you try was to uninstall and then reinstall Adobe Flash Player and Active X control.
I had to do this when I couldn't get sound from YouTube videos. Sometimes it gets corrupted.
I don't know if this is your problem, but there is a chance it could be. Your problem is kind of perplexing, because it is happening on two separate computers. That's very strange. I get sound just fine opening the web pages with Internet Explorer.
If you could get sound in the past, but you can't now, perhaps a system restore is in order. Ted can help you with that.
If you want to give it a shot here are the links for instructions on uninstalling and then reinstalling Adobe Flash.
You might have to reboot after you've completed the process.
Hope it helps.
Steve
How to uninstall the Adobe Flash Player plug-in and ActiveX control
Adobe Flash Player Download Center - Windows