Chave de registro delphi

para todos tem que declarar registry na uses

uses
  registry


Apagar Chave de Registro

procedure TForm2.Button3Click(Sender: TObject);
var
  registro : TRegistry;
begin
  registro := TRegistry.Create;
  registro.RootKey := HKEY_CURRENT_USER;
registro.DeleteKey('Software\Microsoft\Windows\CurrentVersion\Explorer\sua_chave');
end;



Criar Chave de Registro

procedure TForm2.Button2Click(Sender: TObject);
  const
    raiz : string = 'Software\Microsoft\Windows\CurrentVersion\Explorer\sua_chave';
  var
    registro : TRegistry;
begin
  registro := TRegistry.Create;
  registro.RootKey := HKEY_CURRENT_USER;
  registro.OpenKey(raiz, true);
end;


Verificar se Chave de Registro Existe

procedure TForm2.Button1Click(Sender: TObject);
var
  registro : TRegistry;
begin
  registro := TRegistry.Create;
  registro.RootKey := HKEY_CURRENT_USER;

  if registro.KeyExists ('Software\Microsoft\Windows\CurrentVersion\Explorer\sua_chave') then
  ShowMessage('existe')
  else
  ShowMessage('não existe');

end;