RegistryKey hklm = Registry.LocalMachine;
RegistryKey uninstall = hklm.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\");
foreach (string site in uninstall.GetSubKeyNames())
{
    RegistryKey sitekey = uninstall.OpenSubKey(site);
    if (sitekey == null)
    {
        Console.WriteLine(sitekey + "-----" + "IS NULL");
        continue;
    }
    foreach (string s in sitekey.GetValueNames())
    {
        Console.WriteLine(site + "-----" + s + ":" + sitekey.GetValue(s));//在这里获得大小和使用频率
    }
}