unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs;
type
 TForm1 = class(TForm)
 procedure FormCreate(Sender: TObject);
 private
 { Private declarations }
 public
 { Public declarations }
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
var 
 hMenuHandle : HMENU; 
begin 
 hMenuHandle := GetSystemMenu(Form1.Handle, FALSE);
 if (hMenuHandle <> 0) then
 DeleteMenu(hMenuHandle, SC_CLOSE, MF_BYCOMMAND);
end;
end.