How to implement single instance per machine application?

Question

I have to restrict my .net 4 WPF application so that it can be run only once per machine. Note that I said per machine, not per session.
I implemented single instance ap

Answer 1

I think what you need to do is use a system sempahore to track the instances of your application.

If you create a Semaphore object using a constructor that accepts a name, it is associated with an operating-system semaphore of that name.

Named system semaphores are visible throughout the operating system, and can be used to synchronize the activities of processes.

EDIT: Note that I am not aware if this approach works across multiple windows sessions on a machine. I think it should as its an OS level construct but I cant say for sure as i havent tested it that way.

EDIT 2: I did not know this but after reading Stevo2000's answer, i did some looking up as well and I think that the "Global\" prefixing to make the the object applicable to the global namespace would apply to semaphores as well and semaphore, if created this way, should work.