Windows 7 - Media playback stops when certain software opens

Since I installed Windows 7 nearly a month ago, I've been having an issue where all media playback stops. This happens every time I open the Zune software, a lot of the time when I try to play a song from MySpace, and other times when I'm not sure what I've done to cause it.

When it happens, I cannot play files in WMP. The timeline cursor just sits at the 0:00 mark with no error message. YouTube videos will play without sound but videos on other sites such as FailBlog.org will stop after a few seconds.

The only way I can resume media playback is with a system restart.

I'm using the onboard audio on my Asus K8V-MX motherboard, for which I had to manually install the driver and I can't find a newer version.

Does anyone have any ideas about how I could fix this?

Thanks.

Well, without my knowing, this problem seems to have resolved itself. Perhaps an automatic software or Windows update took care of it.