Force-quit a Shell (Windows)

Pass the Shell.PID property to this method (Win32 only):

Function KillProcess(ProcessID As Integer, ExitCode As Integer = 0) As Integer
  Declare Function OpenProcess Lib "Kernel32" (DesiredAccess As Integer, InheritHandle As Boolean, ProcessId As Integer) As Integer
  Declare Function TerminateProcess Lib "Kernel32" (ProcessHandle As Integer, ExitCode As Integer) As Boolean
  Declare Function CloseHandle Lib "Kernel32" (Handle As Integer) As Boolean
  Declare Function GetLastError Lib "Kernel32" () As Integer
  Dim pHandle, lasterr As Integer
  pHandle = OpenProcess(PROCESS_TERMINATE, False, ProcessID)
  lasterr = GetLastError()
  If lasterr = 0 And TerminateProcess(pHandle, ExitCode) Then
     lasterr - GetLastError()
    Call CloseHandle(pHandle)
  End If
  Return lasterr
End Function