Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

uses
   Registry;

 function GetProgramFilesDir: string;
 var
   reg: TRegistry;
 begin
   reg := TRegistry.Create;
   try
     reg.RootKey := HKEY_LOCAL_MACHINE;
     reg.OpenKey('SOFTWARE\Microsoft\Windows\CurrentVersion', False);
     Result := reg.ReadString('ProgramFilesDir');
   finally
     reg.Free;
   end;
 end;


 procedure TForm1.Button1Click(Sender: TObject);
 begin
   // Shows something like c:\Program files 
  // zeigt "c:\Programme" (oder ahnlich) 
  ShowMessage(GetProgramFilesDir);
 end;