I have edited it like you did say, but I still can't get it to work.
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>
GUICreate("Pinger", 200, 100) ; Lager viduet.
$start = GUICtrlCreateButton("ping", 70, 70, 70) ;Lager knappen.
GUICtrlCreateLabel ("Ping adressen:", 20, 10) ; Lager en label
$url = GUICtrlCreateInput (" ", 20, 30, 150)
GUISetState(@SW_SHOW) ; Gjør så vinduet ikke lukker seg.
While 1
$msg = GUIGetMsg()
Select
Case $msg = $start ;gjør så "Vinduet" sine knapper skal fungere
Global $ping = ping (GUICtrlRead ($url), 250)
If $ping Then
MsgBox(0, "Ping", "Pingen er " & $ping)
Else
MsgBox(0, "Error", "error", @error)
EndIf
Case $msg = $GUI_EVENT_CLOSE
ExitLoop
EndSelect
WEnd