Firstly , Thanks for input!

I'm adjusting some settings regarding to the program that I want to start both before it's started and afterwards - when its up and running. It's a GUI-program, so I would like users not to see the console window at all, but that is not highest priority.

You say quote:
"Actually perl internally parses your command to know what to run and which arguments to pass. Hence difference when you add extra quotes."

What does this mean regarding to the console window that won't be killed (or the console windows (not) appearing)? It seems that when I use

my $prg= ' "c:/winnt/notepad.exe" ';

and

exec $prg ;

in the child process there is some other process starting up, which keep the perl program from ending (and thus closing the console window)?! Tom