Rady pana Googla:

; Center Window on Screen
; Author cdkid and Valuater

Func _Middle($win, $txt)
    $size = WinGetClientSize($win, $txt)
    Local $y = (@DesktopHeight / 2) - ($size[1] / 2)
    Local $x = (@DesktopWidth / 2) - ($size[0] / 2)
    Return WinMove($win, $txt, $x, $y)
EndFunc  ;==>_Middle