Looking 4 help

[Mr.Sade]

Hello people

I'm sorry about the title

I'm having another problem.
I'm using SetWindowLong with GWL_USERDATA to store a pointer, doing that I dont have to declare a dinamic array to store the values returned by SetWindowLong and GWL_WNDPROC.
So I have this to store a pointer to the window:

Delphi-Quellcode:

procedure NotepadCreated(Handle: HWND);
var
  Win: PWinInfo;
begin
  New(Win);
  Win^.Handle := Handle;
  Win^.OldPtr := GetWindowLong(Handle, GWL_WNDPROC);
  { lets subclass it }
  SetWindowLong(Handle, GWL_WNDPROC, Integer(@NotepadProc));
  { assign pointer to window }
  SetWindowLong(Handle, GWL_USERDATA, Integer(@Win));
end;

when the hook sends me a message that notepad is clossing I have this:

Delphi-Quellcode:

procedure NotepadDestroyed(Handle: HWND);
var
  Win: PWinInfo;
begin
  Win := PWinInfo(GetWindowLong(Handle, GWL_USERDATA));
  { set oldptr back}
  SetWindowLong(Handle, GWL_WNDPROC, Win^.OldPtr);
  { free memory pointer}
  Dispose(Win);
end;

Well, that works good.
The problem is when closing my application.
I have to set back all notepad pointers so I call CleanNotepadPtrs.

Delphi-Quellcode:

function EnumWins(Handle: HWND; lParam: LPARAM): Boolean;
    stdcall;
var
  szClass: array [0..256] of Char;
  Win: PWinInfo;
begin
  ZeroMemory(@szClass, 256);
  GetClassName(Handle, szClass, 256);
  if szClass = 'Notepad' then
  begin
    Win := PWinInfo(GetWindowLong(Handle, GWL_USERDATA));
    { set back ptr }
    SetWindowLong(Handle, GWL_WNDPROC, Win^.OldPtr);
    { free memory }
    Dispose(Win);
  end;
  Result := True;
end;

procedure CleanNotepadPtrs;
begin
  EnumWindows(@EnumWins, 0);
end;

Well, You see, It's the same as before, but Notepad crashes.
do you know what could I been doing wrong ?
I have also tried to send a message inside NotePadWndProc and
read the pointer (GWL_USERDATA) and then that sets back the pointer (GWL_WNDPROC), but also causes an error

Thank You.