Don,

Then, in the start menu, whether you get to it via searching for it or whether there is a permanent shortcut in the start menu itself, look at the properties for Note.

Somehow, somewhere, something has assigned CTRL + SHIFT + N to make Windows invoke that program.  It is possible, but highly improbable, that this could be the result of a corruption in Windows itself, and they do happen on occasion.

But Windows is never going to fire up a program when a keyboard shortcut is issued unless that shortcut exists in Windows own list of shortcuts I handle.  The most common way of adding to that list is either during the installation of a program or by creating a desktop shortcut and then assigning a keyboard shortcut to that desktop shortcut.
--

Brian - Windows 10, 64-Bit, Version 21H1, Build 19043  

It is the function of creative men to perceive the relations between thoughts, or things, or forms of expression that may seem utterly different, and to be able to combine them into some new forms--the power to connect the seemingly unconnected.

    ~ William Plomer