As Wolfgang has already noted, this thread seems the prosecution of the old one he linked: it is very advisable that questions are not divided into several threads as it becomes difficult for us to follow them.
Given this, the behaviour of the program is clear if you think of the execution of the program. Every time you press the button yout Routine () is called with a different value and runs a loop. Every time, while in the loop it stops other running loops (adding a ProcessSystemEvents () does not alter this, as loop prosecution is not a UI or system event). When the last loop terminates it frees the last-but-one, which eventually will terminate and so on. That's why you see 'Value' content decreasing from the initial one.
What you absolutely need to do is to determine which actions are legal in every moment and what to do in every situation. You say the user needs full control, but is it legal for him to fire the routine more than once (I suppose the loop actually mimics some long-lasting operation like measure, data analysis or so)? What is the function supposed to do if concurrently running two or more times? Can it actually do so? May there be conflicts on shared resources / data or not? You said nothing about the function scope, so you'll have to answer to these questions yourself and then reconsider the code to make it operable in the situation you have to address. Please ask yourself also if user desires can actually be addressed or if they are simply too much for the system to handle them properly.
