Single Instance WinForms application example.
Example solution containing my OneInstance static class.
This is a way to handle WinForms applications that you only want to run one instance at a time. It uses a Notification Icon and a non persistent main Form (default solutions have persistent main Forms)
This example solution is commented enough to provide full info on how to use the OneInstance class. Just pull the OneInstance.cs file out and include it in your solution, follow the same steps as in this example and you should be good.
Remember to change the icon.