It looks like you may need to download and reinstall the Sony "Drivers and Utilities" items from the Sony site. See the discussion at the link below:
Hope this helps.
I recently upgraded from Vista Basic to Vista Home so I could connect my Marketplace to my XBOX 360. Well that worked, but now I have no sound. I checked and my drivers are updated when looking in Device Manager: SigmaTel High Definition Audio CODEC
Here is when I clicked "Web Help" from Windows Media Player (after I tried to play a song).
This error might have been triggered by an error in another program or component of Windows. The following information describes the original error.
Original Error Code: C00D4E84
Original Error Message: No audio playback device was found.
Thanks for reading all this...and your support! I need soemone's help.