...
# launch the window
$pid = fork;
unless( $pid )
{
	`MyGUI.exe`;
	exit 1;	
}

# much code to manipulate the GUI, etc here..

# now close the GUI..
&PressAButton( $gui_handle, "&Close" );

# should be done here

##</code><code>##

...
# launch the window
$pid = fork;
unless( $pid )
{
	`MyGUI.exe`;
	exit 1;	
}

sleep 10; # long enough for the GUI to launch
# here is the kicker:
kill 9, $pid;
# now continue with my usual testing...