scripting of bgsound tag doesn't work on IE7 of Vista

I use site http://www.thefreedictionary.com frequently. One feature of the
site is being able to pronounce a word implicitly by clicking an icon. No
explict prompt of downloading .wav file and launching a player is needed. The
way the pronounciation is implemented is through javascripting of the bgsound
html element.
This works for all versions of IE (including IE7) but after I installed a
fresh Vista last month it stopped working. But then somehow it worked for a
while and a couple days ago it stop working again. I think there might be
some windows updates tweaked some security settings. But I have no clue.
Does anyone experienc same problem and found the cause?