Avoid from being two same application in one machine

[Grey]

I need to block user from being open two same applications in one machine
and control a user can only login the application once. the application
would prompt message to inform user that he/she has already been login the
application and ask him/her to close the previous session. Is it use Session
to do that or any other ways??

Million Thanks...

 

[Scott Allen]

Hi Grey:

It's difficult to do without frustrating users at one point or
another, and something I'd avoid trying. One of the problems is - you
don't know when a user has ended a session or logged out.