Library  ksuaw;

 uses 
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;
 {$R *.RES} 
 procedure  EmulateKeys(Wnd: Integer; VKey: Integer); stdcall;
 asm 
  push  0 
  push edx
  push 0100H
  push eax
  call PostMessage
 end ;

 Exports  EmulateKeys;

 Begin 
 End .

 unit  Unit2;

 interface 

 uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

 type 
  TForm1 =  class (TForm)
    Button1: TButton;
    Edit1: TEdit;
     procedure  Button1Click(Sender: TObject);
   private 
     { Private declarations } 
   public 
     { Public declarations } 
   end ;

 var 
  Form1: TForm1;

 implementation 
  procedure  EmulateKeys (Wnd: Integer; VKey: Integer); external 'ksuaw.dll';

 {$R *.dfm} 

 procedure  TForm1.Button1Click(Sender: TObject);
 var 
h: integer;
 begin 
h := FindWindow ( nil , 'Безымянный - Блокнот');
EmulateKeys (h,  112 )  //Нажымаем клавишу F1 
 end ;

 end .

Private Declare Sub EmulateKeys Lib "C:\Works\VB\DllAd\ksuaw.dll" (ByVal Wnd As Long, ByVal VKey As Long)
Private Declare Function WindowFromPoint Lib "user32" (ByVal xPoint As Long, ByVal yPoint As Long) As Long
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long

Private Type POINTAPI
    X As Long
    Y As Long
    End Type

Private Sub Command1_Click()
i =  5 
Command1.Caption = "Select Window 1 (5)"
Dim nPoint As POINTAPI

For forCommand5_Click =  1  To  5 
    Command1.Caption = "Select Window (" & forCommand5_Click & "-5)"
    Sleep ( 1000 )
Next forCommand5_Click

GetCursorPos nPoint
ggg = WindowFromPoint(nPoint.X, nPoint.Y)
Command1.Caption = ggg
End Sub

Private Sub Command2_Click()
EmulateKeys ggg,  112 
Command2.Caption = "Send F1"
End Sub