Audio missing from media files

I've got a lot of videos from the recent E3 expo and I've been watching them one last time before I delete them, but there's no sound in any of them now, all of a sudden. This is affecting all media files, yet the familar 'beep' when you do something that Windows doesn't agree with is still there. What could be causing this?

 

I've restarted the PC and sound is fine again. There was an audio error with Media Player Classic, it said it needed to download an audio codec and gave this reponse:

Stream 1
Avi Splitter (low merit)
MPEG-1 Audio Decoder
Audio Switcher

But when I clicked the button to 'go the website to download the codec', the page is down.

Very very strange!

 

Control Panel/sound............Make sure it is not muted.........then try Advanced for anything muted.

OK scrap that.

What version of WMP is it? Was it OK before playing without the codec it wants to download?

 

Version 6.4.8.7

It was fine then, now again no media files have sound. What on earth could be doing this?

The 'old' Windows Media Player (mplayer2.exe I think it is) does give me some info, a dialog box comes up with this message:

Cannot play back the audio stream: no audio hardware is available. (Error=00040258)

Then it plays the video muted.

 

Seems like you have a sound-card problem. Check in device manager for your sound device - and maybe reload the drivers for it, or check for newer drivers on-line.

Whenever I've seen that type of error message, it turned out to be driver related - rarely bad hardware.