unit Unit1;

interface

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

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

var
  Form1: TForm1;
  reg: TRegistry;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
   reg:=tregistry.create;
   reg.rootkey:=hkey_current_user;
   if reg.openkey('software\My Project', true) then
   begin
       reg.WriteString('parameter', 'value');
       reg.closekey;
   end;
   reg.free;
end;

end.