unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

    TOSInfo = class(TObject)
  public
    class function IsWOW64: Boolean;
  end;

var
  Form1: TForm1;


implementation

{$R *.dfm}

class function TOSInfo.IsWOW64: Boolean;
type
  TIsWow64Process = function(
    Handle: THandle;
    var Res: BOOL
  ): BOOL; stdcall;
var
  IsWow64Result: BOOL;
  IsWow64Process: TIsWow64Process;
begin
  IsWow64Process := GetProcAddress(
    GetModuleHandle('kernel32'), 'IsWow64Process'
  );
  if Assigned(IsWow64Process) then
  begin
    if not IsWow64Process(GetCurrentProcess, IsWow64Result) then
      raise Exception.Create('Bad process handle');
    Result := IsWow64Result;
  end
  else
    Result := False;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  if TOSInfo.IsWOW64 = True then begin
  Label1.Caption := 'You are on a x64 machine.';
  //ShowMessage('Running on 64-bit OS!!');
  Button1.Enabled := False;
end
 else
  begin
  Label1.Caption := 'You are not on a x64 machine.';
  //ShowMessage('NOT running on 64-bit OS!!');
  Button2.Enabled := False;
end;
end;

end.