第一个文件 ,窗体1 ,一般可以是登录界面
unit Unit2;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
    TForm2 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form2: TForm2;
implementation
uses Unit4;
{$R *.dfm}
procedure TForm2.Button1Click(Sender: TObject);
var  nform:TForm4;
begin
   nform:= TForm4.create(Application);
   nform.show;
   Form2.Visible:=false;
end;
end.
第二个文件 窗体二,一般可以是主题界面
unit Unit4;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;
type
  TForm4 = class(TForm)
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form4: TForm4;
implementation
//定义了一关闭的方法,当窗体二关闭的时候 ,整个程序关闭
 function closeProcess(x, y: Integer): Integer;
           stdcall; external 'kernel32.dll' name 'TerminateProcess';
{$R *.dfm}
procedure TForm4.FormClose(Sender: TObject; var Action: TCloseAction);
begin
     closeProcess(-1,0);
end;
end.