Microsoft Agents won't talk.

I've used "agents" for years, but can't get them "talking" in Vista. The
following components have been installed ( just as in prior versions of
Windows), but all I get are "chat bubbles" without sound.

actcnc.exe
SpchCpl.exe
spchapi.exe
MSagent.exe
tv_enua.exe

Any clues? Thanks in advance.