>>C propgram is fine but the quickest way it's may be API call:
>> DECLARE INTEGER FindWindow in win32api INTEGER,STRING
>> if FindWindow(0,oSystem.Apptitle)<>0
>> QUIT
>> endif
>>Put this code to first lines of your App but after oSystem app object created.
>
>No, this is certainly not the quickest way because you have to load another instance of Visual FoxPro in memory before executing the first line of your code. And, in most case, you'll run out of memory before it succeed loading another time.
>
>What can be faster than clicking on the icon and having an instant switch to the application that was already running? :)

Surely, you right. I meant the quickest way from VFP programmer standpoint (you don't need to go outside VFP). By the way I'm not sure about running out of memory. Actually I have system with couple VFP/VB executables running concurrently and memory is OK even on low-end (16M) workstations.