I don't know if anyone else has had this problem with vista - any swf file with sound shows a marked delay before the sound is played. Its not just a flash issue, I have a delphi program with the same problem.
I finally found a workaround here:
http://dalefraser.blogspot.com/2007/05/ ... ssues.html
You can get to the dialog box shown from:
Control panel -> Additional options -> Hardware + sound (on the left) -> Sound -> Manage audio devices -> speakers -> properties.
Not exactly obvious - is it?
Hope this is of help to someone