Do user-specified shortcut keys for Windows only work on certain directories?

I am trying to mute my computer's speakers by pressing a shortcut key. My keyboard doesn't have a button for 'Mute' or any other extra multimedia buttons.

With my keyboard, I mute my computer by creating a shortcut to NirCmd with the mutesysvolume 2 argument (toggle mute on/off). I then assigned this shortcut, a shortcut key of Ctrl + Alt + M by right clicking the shortcut > Properties > Shortcut > Shortcut key.

However, this only works if I create the shortcut file in the desktop or a subfolder in the desktop.

I initially tried creating the shortcut in the NirCmd directory in the Program Files folder, but no luck - the shortcut key doesn't work (but the shortcut does). I also tried creating the shortcut in a subdirectory one level under C:\, still to no avail. I then tried creating the shortcut at one directory level under C:\Users\username but the shortcut key still doesn't work. The shortcut keys won't work even if I move the shortcut file (.lnk) to the desktop.

I tried moving nircmd.exe to the Windows directory so I could call it without specifying the directory, but I still get the same issues above.

Anyone know the reason why the shortcut key does not work if I put the shortcut file in the directories I mentioned?

I am using Windows 7, 64-bit with the 64-bit version of NirCmd.

Answer

It must be in the Start menu folders or the Desktop.

As per the Microsoft Support page, Shortcut key for shortcut does not work:

Symptoms

You are unable to run a shortcut by pressing its shortcut key.

Cause

Shortcut keys work only for shortcuts on the desktop or in the Start menu hierarchy.

Resolution

Make sure that the shortcuts for which you want to use shortcut keys are on the desktop, on the Start menu, or in the Windows\Start Menu\Programs folder.

More Information

Shortcut keys work differently depending on the location of the shortcut. If the shortcut is on the desktop or in the Start menu hierarchy, you can use its shortcut key to start the assigned program, or switch to the program if it is already running.

If the shortcut is not on the desktop or in the Start menu hierarchy, you cannot use its shortcut key to start the assigned program, but you can use its shortcut key to switch to the assigned program if it is already running.

NOTE: Shortcut keys may not work for some programs. For example, shortcut keys do not work for items on the Quick Launch bar.