OneInst.zip-simple component that prevents a 
user from running multiple instances of the 
same app. The second instance will be closed 
and the first one activated. You may define 
a message text to show and a title for that 
dialog. Also you can write a handler for an 
OnAnotherInstance event. Usually there is no
need to modify Message and Mutex properties,
but you may change them anyway but be careful
to set them to a different value in the
different applications.