Sean & Scott [fixed link]: The example you gave is great, although I would suggest something a little more robust, specifically you probably want to allow data to pass between the already running instance and the new one created (this allows you to marshal the command line arguments). I wrote an article on this last year... however supporting data marhsalling makes the code much much more nasty.

BTW, there were some minor bugs in the single instance logic that were fixed in next article in the series.