Is there a code that will only allow one instance of your app to be opened....




Then when the code detects that another instance is running is there a way to pass the command line on to the already running instance.....


What i have is my program opens a mp3 file when you double click on them....but when i click on a mp3 it opens my app and then i click on another mp3 it opens another one of my apps. So each time i click a mp3 i get a new app.

Hope this makes sense.
any help would bee great...
Thanks