code: def _getRegisteredExecutable(exeName):
      
      registered = None
      if sys.platform.startswith('win'):
          if os.path.splitext(exeName)[1].lower() != '.exe':
              exeName += '.exe'
          import _winreg
          try:
              key = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\App Paths\\" +\
                    exeName
              value = _winreg.QueryValue(_winreg.HKEY_LOCAL_MACHINE, key)
              registered = (value, "from HKLM\\"+key)
          except _winreg.error:
              pass
          if registered and not os.path.exists(registered[0]):
              registered = None
      return registered
docs: Windows allow application paths to be registered in the registry.