In Microsoft TechNet forum I saw an interesting problem.Here it goes:
The Volume Bar appears at the top left corner of the screen when adjusting sound, it momentarily obstructs for a few seconds then disappears.Is there any way to remove this?
Unfortunately there is no registry hack to make it disappeared.At best you can minimize the notification time.To do this:
Open the Settings Charms
Select Change PC Settings
Select Ease of Access
Scroll down to Other Options
Make sure Show notifications for 5 seconds.