How to prevent multiple launch of a program from Explorer window ?

Hello

I run begin.btm by double-clicking it from an Explorer window. It launches

-----------Code.btm-----------
MSACCESS.EXE test.mdb
bsa.bat
-------------

Often my computer freezes/I click too much and it launches multiple copies of begin.btm/Code.btm/MSACCESS.EXE. How to prevent this/best way to check if Code.btm or internal commands are already running ?

thanks