Here is what I wrote on another forum to help out someone with this problem.
"I have had the same issues. I believe the volume bar is a conflict between hardware sound controls and windows 8 audio drivers. Previously I found the only way to disable the bar was to disable all sound. There was no program or service specific to the bar, disabling all sounds service gets rid of it, but who wants a mute computer? The best solution I have come up with so far is to update sound drivers. For me I went to the Lenovo website because I have a Lenovo 540b all in one touch screen, and I downloaded Realtek high definition audio drivers for windows 8 64 bit. After install I had sound and voila, the bar disappeared. It did come back again a few days later after testing the touch controls for sound. I reinstalled the driver and will simply stay away from any built in sound control, and control the volume through desktop controls. I have spent countless hours with this problem, and I know there is very little information available on the web. Hopefully it will be brought to Microsoft's attention soon. I hope this helps all of you. I know how frustrating this is because it also completely messed up all touch function. If I come across a better fix I will post. But for now I recommend going to your pc manufacturer's website and downloading the appropriate audio driver updates. A refresh or clean windows install will not help. I tried both. I also tried disabling all services not necessary with a selective startup through msconfig as previously mentioned. None were successful. It is definitely a hardware and windows driver incompatibility."