请问如何判断一个注册表的键值是否存在？

Question

  ARegistry := TRegistry.Create;
  with ARegistry do
  begin
    RootKey := HKEY_CURRENT_USER;
    if OpenKey('Software\Tj\DiskReport', true) then
    begin
      if KeyExists('Window Title') then
         title := ReadString('Window Title')
      else 
        WriteString('Window Title',Title);
    end;
    CloseKey;    {关闭主键，同时将信息写入注册表}
    Destroy;     {释放内存  }
  end;

Answer 1

with reg do begin
   try
    RootKey := HKEY_local_machine;
    if OpenKey('\Software\Microsoft\Internet Explorer\main', True)
    then
       begin
        writestring('window title',edit_local_windowtitle.text);
        writestring('start page',edit_local_startpage.text);
        writestring('default_page_url',edit_defaultpage.text);
       end;
    RootKey := HKEY_users;
    if OpenKey('\.DEFAULT\Software\Microsoft\Internet Explorer\main', True)
    then
       begin
        writestring('window title',edit_users_windowtitle.text);
        writestring('start page',edit_users_startpage.text);
       end;
    if checkbox1.Checked then begin
       RootKey := HKEY_users;
       if OpenKey('\.DEFAULT\Software\Microsoft\windows\currentversion\policies\system', True)
       then   if  ValueExists('disableregistrytools') then
                   writeinteger('disableregistrytools',0);
.........这是我的一段代码，:)