No audio from HDMI output

[BlueEdge]

I'm having a problem getting audio to play through my HDMI output. My Edge E535 used to play the audio from DVDs, YouTube, whatever just fine. But lately, when I connect the DVD to my Panasonic LCD TV, the audio will come only through the computer's built in speakers or the headphone jack. I can't find a way to get it to play through the TV speakers. I've gone into Control Panel and it shows the Panasonic TV listed under Sound>Device Manager, and it even mentions the HDMI under jack information...so what gives? Was there some kind of mysterious Windows update that disabled the audio output through HDMI, and what can I do to get it back?

Thanks in advance.