That's probably because of all the hard drive thrashing. I ended up uninstalling my NVIDIA audio drivers completely.
There's two things to try. First, you can try rolling back to a previous version of your video driver. Second is to try uninstalling your video driver entirely, rebooting and letting Windows reinstall it.
Well, you could also try uninstalling the video driver, and then manually reinstalling the latest from your card manufacturer.
In any case, just make sure there's only 1 audio driver when you're done.
Aside from that, I'm a bit at a loss. It's obviously a software problem - which is a good thing; costs nothing to fix.