I recall an article in FPA with some rather circuitous code which accomplished this. It was intense, and I assume it's because it was made pretty bulletproof. I'm sure a search of back issues will reveal it.

>I remember using the foxtools library to ensure that only one instance of my app was running, but I seem to have misplaced that code :)
>
>Has anyone else used foxtools to accomplish this and could you post / email me a sample of your code?
>
>TIA