Program running?
 

Well, i'm sorry if this question has been asked before, I used the Search but it couldn't find a posts meeting my criteria

How can I see if for example the applacation "BioDuo.exe"
is running and if so give a messagebox?

There is a plugin in the Wiki called FindProc that will do that for you.

http://nsis.sourceforge.net/wiki/Find_Process_By_Name

You can also use FindWindow which is in the NSIS Docs if you know the title of the window and it has a window.

-scully13

Thanks for your quick replay scully13 ;)