I have a T500, with the latest updates from Lenovo and Microsoft. It's running Windows 7 Professional, 64-bit.
When I press one of the silver volume buttons above the keyboard (volume up, down, or mute) a black box appears near the bottom of the screen with a speaker icon, and a gray and white bar indicating the level, and white number on the right. This seems to work correctly, and the buttons make the number go up and down, and white bar grow and shrink as expected. Similarly, the Brightness (Fn-Home and Fn-End) make a similar box appear, which also seems to work correctly.
The problem is that after I've done this, the black box does not go away, and it obscures that area of the screen. I expect it to stick around a couple seconds after I've pressed the buttons. But it is still sticking around HOURS after I've pressed the buttons. If I Lock the computer (using Windows-L) the lock screen does not show the black box, but when I unlock it, the black box is there again. This seems to happen every time I've used either the volume or brighness buttons. The only way I've found to make it go away is to restart the computer.
For users with Windows 7, :
Right-click on desktop
Choosecreen resolution (usually near the bottom)
Click: Advanced settings (on the right)
Click: On Screen Display (tab along the top)
Set the Fadeout time, and click Apply or OK.
Note : that the tab in step 4 will not be present if you haven't installed (or uninstalled, as a work-around will need to be done) within the Hotkey utility.