Second copy of app launching

[Ray Horsley]

This could be an old topic.  Does anyone have a way to detect if a copy 
of an application is open?  I need this to prohibit launching my app 
when a copy of it is already running.  It's only a problem on Windows 
since the Mac OS simply brings the already open app to the front 
instead of launching a second copy.  A list of all open applications 
would be nice.

Thanks,

Ray Horsley
LinkIt! Software