So here is what I did:
- Navigate to %systemroot%\System32
- In this folder a file called Narrator.exe is to be found
- Right click the file and choose Properties
- Choose the Security tab and press Advanced
- In the top of the window press Change to change the Owner permissions
- In the text field write your username and press OK to all the dialogs
Now you should be able to change the permissions of the file, this is where we remove all the permissions from your user and the user back to system, this way your user will not be able to start the Narrator.
- Right click the Narrator file again and choose Properties and Security tab
- Press Advanced
- Now that you are the owner you can change permissions for other users. Choose your own user and press Edit
- Remove the Read & Execute and Read permissions and press OK
- Now press Change in the top under Owner and write system in the text field
- Press OK to all dialogs
Now you should have removed all your permissions and changed the owner permissions the system, which means you cannot open the program anymore. When pressing the Win+Enter combination nothing should happen now. Enjoy!