Weird Speaker/Music/Sound problem?

Okay, this is a weird problem. I'll try to explain it as clearly as possible.

So first of all, my speakers are perfectly fine. The sound is clear, and everything works. However, i think that the software/drivers are to blame, but i don't know how to fix it.

When I sign onto vista, everything goes well. There are all the welcome sounds and stuff, and even the guy from Avast updater that says my files have been updated works. If I go onto youtube, or something, and I play something, the sound works fine. Everything for everything seems dandy, except..

My volume bar is possessed. It goes up and down. I'm not touching the control panel above my keyboard, nor am i doing anything with the volume bar myself. The Volume goes up and down, as if it were undulating. But it doesn't happen constantly. Every few seconds it would do that. If i open the volume controls in the task bar, I actually see the volume control scroll up and down.

When I go to the Sounds option in the control panel, it says that there's a driver that has something wrong with it, and it disables it for me. But the problem persists. The bar still goes up and down uncontrollably and unpredictably.

And a possibly related, but also possibly unrelated problem, is that whenever i try to play my MP3s in either Windows Media Player or iTunes, nothing happens, and it says that the file is being used somewhere else, or i can't access the file, or i don't have permission to.

how do i fix this?

 

Sorry to start with the obvious, but have you tried removing and reinstalling the soundcard driver and any special mixer software related to it?

If you start in Safe Mode, do you still see the volume bar move of its own accord or does that stop it. In that case, there's obviously some piece of software doing. Might try going into your processes list and killing things one at a time till it stops.

As for the Mp3s not playing, are they DRM free or do they have permissions associated with them? Did you buy them from iTunes, rip them from a CD, or download them? Have you tried to play them on any other computers, Mp3 players, etc? Did they ever work on the laptop?

I'd try reinstalling the drivers first, and if there is a device that's being disabled for not functioning correctly I'd remove and reinstall it as well.