I need to make sure that there is ONE only ONE instance of my app is running

App.PrevInstance only checks for previous instances within the current session.

I need to make sure that there is only one instance across ALL users.


Listing processes in the TaskManager might be an option but are there any other methods?

I thought about settting a flag in a common file which clears when the app stops, but I don't want to do that because it might not get cleared if the program exits ubnormally.