Microsoft Natural Ergonomic Keyboard 4000 (and others, I suspect) on Windows 7:
Volume controls and Mute button don't work... Running IntelliType Pro 7.1
Here's the fix:
Go to the Services MMC (I use the shortcut provided by the the awesome new Task Manager).
Turn on the "Human Interface Device Access" service.
Set the Startup Type: to Automatic.
(On older versions of Windows - Suggested back in 2006)
!!!!! UNTESTED !!!!!
Volume control seems to work fine if you start the "HID Input Service".
If you are not able to start it (happened to me), fire up the registry
editor and find:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic
es\HidServ\Parameters
If there's a string called "ServiceDll" delete it, and create a new one
(expandable string named "ServiceDll") with this value:
%SystemRoot%\System32\hidserv.dll