Audio is muted in ALL video files (avi, rm, DVD, etc) WHAT?!

[Karate Media]

Strangest problem I've seen recently -- any ideas?

All of the sudden today I've got (almost) no audio in my video files! If I crank the speakers, I can almost hear the sound in .avi files and DVDs, and I can hear faint, distorted squawks from real media files. Video playback is fine, but audio is shot. This is happening across the board, in Windows Media Player, Premiere, PowerDVD, Real Player, etc...

MP3s and "standalone" wave files play fine in both WMP and MusicMatch -- but wave files that contain the audio for .m2v files suffer from the "mute problem."

The only new addition to my system (hardware or software) is a Western Digital harddrive, which I installed as a slave drive earlier this week. Funny thing is, the drive's been installed for days, but this audio problem just cropped up today. Since adding the slave, I've captured about 4-5 hours of video and spent a few hours editing. In fact, just last night I edited some footage and burned a DVD with no audio problems whatsoever. I then turned off the computer. First boot of today, and all silence breaks loose.

Can anyone think of what would effect all video files, but not "pure" audio files?

I am running Windows XP and using Sound Blaster Audigy Platinum. Anything else you'd need to know?

Thanks, guys...

[Karate Media]

Update

Slight workaround for the problem, but it creates more questions than it answers...

It seems I can go to Adjust Audio Properties ->Speaker Settings -> Speaker Volume, where I am given level sliders for Left and Right channel. If I slide one channel down to zero, then the other channel will work as a "master slider" for both channels. I can then get full-volume audio for my video files. If they are both at the same level, then they cancel eachother out, causing the muted audio problem.

It doesn't matter which channel, left or right, that I slide down to zero, just as long as the two channel have different output values.

I've run all of this by a couple of my friends, but none of us can seem to figure this one out, short of just replacing the card, which is not high on my list of desirable fixes...

With this added twist, anyone get any ideas?

[Tommyknocker]

Did you reload your drivers?

[Karate Media]

Yep -- removed and reloaded the nvidia and soundblaster drivers. I was about ready to do a complete reinstall of the OS when I realized I could just fiddle with the sliders for a temporary fix...

[txpharoah]

Be sure the cables are plugged in and no dust is lodged in the cable holes.

[Karate Media]

No dust...but remember, MP3s and .wav files play fine -- it's just the video files (mpg, .rm, even DVDs) that have trouble with audio... Is there a separate part of the hardware that handles the audio from video files?