Volume control automatically reduces and slides down to zero
We had a problem with one of our Windows 7 laptops this week where the volume control slider insisted on automatically sliding down to zero (i.e. no sound). Dragging it back up didn’t help, as it automatically slid straight back down to zero again!
After much searching around, followed up updating multiple drivers to no effect, we discovered how to fix it. The problem is caused by a mouse with a wheel, where the wheel can be used to reduce sound volume but, in this case, gets carried away and does it all the time. The fix is simple – unplug your mouse, reboot the laptop, then when the laptop has re-booted fully, plug your mouse back in again. Hey presto, the volume control no longer slides down!
Hope this helps someone with the same problem – if you happen to come across this post via a search engine and this helps you, it would be great if you were to take a second to leave a comment. It’s always interesting to see who drops by and where they are from!

Good post. We started having this problem two days ago with our Windows 7 laptop. We have a USB wireless mouse with a wheel that can adjust the volume. We’ll try your solution by turning the mouse off and rebooting, then powering up the mouse and see how it goes. But your post is helpful because at least it pinpoints the likely problem.