Every time I sleep or restart my computer (PC), I get the "your audio hardware has changed" notice - I go to my audio hardware and nothing has changed. I just click OK and it's fine, but EVERY TIME. What's happening?
I think it's probably a function of Microsoft Active Socket Sensing. It's really annoying, and you can't turn it off (or not in any way that I've discovered yet). Just unplugging a pair of headphones is enough to set it off. Other things that can do it are default sound settings resetting themselves if you have any sort of settings protection software running.