type
 TPasswordAction = (paSet, paChange, paRemove);
 ....
function ChangeAccessDBPassword(DatabaseName: string; action: TPasswordAction;
 OldPassword: string = ''; NewPassword: string = ''): boolean;
var
 DAO: _DBEngine;
 db: Database;
 ClassID: TGUID;
 V35, V36: string;
 oldPass, newPass: string;
begin
 Result := false;
 V35 := 'DAO.DBEngine.35';
 V36 := 'DAO.DBEngine.36';
 try
  try
  ClassID := ProgIDToClassID(v36);
  except
  try
  ClassID := ProgIDToClassID(v35);
  except
  raise;
  end;
  end;
  DAO := CreateComObject(ClassID) as _DBEngine;
  if action = paSet then
  begin
  db := DAO.OpenDatabase(DatabaseName, true, false, '');
  db.NewPassword(#0, NewPassword);
  end
  else
  begin
  db := DAO.OpenDatabase(DatabaseName, true, false, ';pwd=' + OldPassword);
  if action = paChange then
  db.NewPassword(OldPassword, NewPassword)
  else
  db.NewPassword(OldPassword, #0);
  end;
  Result := true;
 except
  // выводим сообщение о ошибке
  on E: Exception do
  begin
  Result := false;
  ShowMessage(e.message);
  end;
 end;
end.

procedure TForm1.Button1Click(Sender: TObject);
var
 newPass: string;
begin
 if InputQuery('New password', 'Enter new password', newPass) then
  if ChangeAccessDBPassword(ExtractFilePath(ParamStr(0)) + 'db2.mdb', paSet,
  '', newPass) then
  ShowMessage('OK!')
  else
  ShowMessage('Error!');
end;
//изменяем пароль
procedure TForm1.Button2Click(Sender: TObject);
var
 oldPass, newPass: string;
begin
 if InputQuery('Old password', 'Enter old password', oldPass) then
  if InputQuery('New password', 'Enter new password', newPass) then
  if ChangeAccessDBPassword(ExtractFilePath(ParamStr(0)) + 'db2.mdb',
  paChange, oldPass, newPass) then
  ShowMessage('OK!')
  else
  ShowMessage('Error!');
end;
//удаляем пароль
procedure TForm1.Button3Click(Sender: TObject);
var
 oldPass: string;
begin
 if InputQuery('Password', 'Enter password', oldPass) then
  if ChangeAccessDBPassword(ExtractFilePath(ParamStr(0)) + 'db2.mdb',
  paRemove, oldPass, '') then
  ShowMessage('OK!')
  else
  ShowMessage('Error!');
end;