Resolve null value when accessing registry in C#

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C#

ASP.NET

forms

WMI

registry

Hi all. Ok look at my code:

//get Windows OS Key
            byte[] id = null;
            var regKey = Registry.LocalMachine.OpenSubKey("SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion");
            if (regKey != null)
            {
                id = regKey.GetValue("DigitalProductId") as byte[];
                inv_oslicenseTB.Text = id.ToString();

I keep getting null value for id. It's ruining everything. Either I'm looking for the Windows OS License Key in the wrong place (although when i checked in the regedit console, the "DigitalProductID" had a full value in it) OR can't access because of permissions.

I added an app.manifest in there and configured these lines:

<requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
<!-- If your application is designed to work with Windows 7, uncomment the following supportedOS node-->
      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>

      <!-- If your application is designed to work with Windows 8, uncomment the following supportedOS node-->
      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"></supportedOS>

      <!-- If your application is designed to work with Windows 8.1, uncomment the following supportedOS node-->
      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>

still get null value. What am I doing wrong, or is there a different way to get the OS License key?