unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  TWin32Version = (wvUnknown,
                    wvWin95,
                    wvWin98,
                    wvWinNT,
                    wvWin2000) ;
function GetWinVersion: TWin32Version;
var
  Form1: TForm1;
implementation
{$R *.dfm}
function GetWinVersion: TWin32Version;
begin
  Result := wvUnknown;
  if Win32Platform = VER_PLATFORM_WIN32_WINDOWS then
    if (Win32MajorVersion > 4) or
       ((Win32MajorVersion = 4) and
       (Win32MinorVersion > 0)) then
      Result := wvWin98
    else
      Result := wvWin95
  else
    if Win32MajorVersion <= 4 then
      Result := wvWinNT
    else
      if Win32MajorVersion = 5 then
        Result := wvWin2000
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  case GetWinVersion of
    wvUnknown : ShowMessage('Gak Diketahui');
    wvWin95 : ShowMessage('Windows 95');
    wvWin98 : ShowMessage('Windows 98');
    wvWinNT : ShowMessage('Windows NT');
    wvWin2000 : ShowMessage('Windows 2000');
  end;
end;
end.