I suddenly can get no audio to play through WMP in either v6.4 or v10. Video
plays by with no audio. No audio streaming, no nothing. Here are the gruesome
details.
Sorry for the length, but it appears that some people get hostile without
details.

Does the file mmswitch.ax exist on your system?
No

What operating system are you using?
WinXP SP2 with all available patches applied via Microsoft Update

What exact version of Windows Media Player are you using?
WMP6.4.09.1130
WMP10.00.00.3802

What type of issue are you having?
Audio does not play using Windows Media Player (versions shown). Videos AVI,
MPEG, WMV play the video, but with no sounds. See below for errors

Does this happen in other players?
The same files will play using Winamp, Nero, and a couple other AV tools.

Does it happen in/with both "mplayer2.exe" and "wmplayer.exe", if applicable?
Yes

Does this happen for files saved locally, files played back from the
Internet, or both?
Both

Does this happen only if the file has video, or does it happen for all files?
Audio only and the audio content of video

What type of file are you trying to play? Is it an MPEG, ASF, AVI, MIDI,
WAV, or what?
MP3, WAV, AVI, MPEG. Pretty much any file with audio in it.

Does this happen for all files of that type, or just certain ones? Pretty
much anything with audio, but formats like OGG and AC3 not tested. I don't
use them.

What are the steps that you follow in order to produce the error?
Either double-click the file in explorer or File->Open from within WMP

What are you doing when you get the error?
That's a silly question. Staring at the computer.
Nothing but trying to play the music.

How could someone else cause the error to happen their computer?
I have no idea.

If the problem occurs with content on the Internet, what URL do you use to
encounter the problem?
Any streaming WMV from Amazon.com will (not) work. CLick the link and
nothing happens. Yes I have my popup blockers turned off.

What video card do you have?
NVIDIA FX700 Personal Cinema

What sound card do you have?
Built-in to motherboard. NVidia Chipset

Does this same error occur on any other computer?
No

If this is a networking problem, what is your networking configuration?
Not a network problem

If there's an error code, what is it? What exactly does the error text say?
Most critically, what is the error code number if present?

In WMP6.4 playing an MP3,it tries to download a codec and fails giving:
ClassFactory cannot supply requested class
Unable to download an appropriate decompressor. (Error=80040200)
ClassFactory cannot supply requested class (Error=80040111)

In WMP6.4 playing an MPG,it tries to download a codec and fails giving:
Unable to download an appropriate decompressor
Unable to download an appropriate decompressor. (Error=80040200)
However the video still plays, but without sound

In WMP10 playing an MP3, it tries to download a codec and fails giving:
The specified module could not be found
8007007E

In WMP10 playing and MPEG, it tries to download a coded and fails with:
Error downloading codec
No error code is provided. However the video still plays, but with out sound

In WMP10 playing an WAV, it tries to download a codec and fails giving:
C00D109B
Windows Media Player cannot play the file. One or more codecs required to
play the file could not be found.

If you hit a crash and get the opportunity to send an error report, do so!
Then go to the Event Viewer in Administrative Tools (you can manually run
this with the commandline '%windir%\system32\mmc.exe"
"%windir%\SYSTEM32\eventvwr.msc" /s' if you need to). Go to the Application
log in Event Viewer. Look for the "Error" in that list - there should be two
for your latest crash. The most recent one should have a "Fault bucket"
number. What is that number?
It's not crashing

What WMP6 version does this page detect? WMP6.4.09.1130
What WMP7+ version does this page detect? WMP10.00.00.3802

I can also provide nauseating details on the DirectX and codecs installed if
some can help and wants to know.

Thanks,

Keith