Узнаём Windows версию с помощью WMI

  public static string GetWindowsVersion()
  {
    string sWindowsVersion = "";
    string sQuery = "SELECT * FROM Win32_OperatingSystem";
    ManagementObjectSearcher oManagementObjectSearcher = new ManagementObjectSearcher(sQuery);
    foreach (ManagementObject oManagementObject in oManagementObjectSearcher.Get())
    {
    sWindowsVersion = string.Format("{0}| {1}", (string)oManagementObject["Caption"], (string)oManagementObject["OSArchitecture"]);
    }
    return (sWindowsVersion);
  }