HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProductId not found running 32bit app on 64bit Windows

you must use the KEY_WOW64_64KEY value when open the Registry with the TRegistry class.

from MSDN :

KEY_WOW64_64KEY Indicates that an application on 64-bit Windows should operate on the 64-bit registry view. This flag is ignored by 32-bit Windows.

This flag must be combined using the OR operator with the other flags in this table that either query or access registry values.

try this sample app.

{$APPTYPE CONSOLE}

uses
  Windows,
  Classes,
  registry,
  SysUtils;


procedure ReadRegistry;
var
  Registry: TRegistry;
  List    : TStrings;
begin
  Registry := TRegistry.Create(KEY_WRITE OR KEY_WOW64_64KEY);
  //Registry := TRegistry.Create(KEY_READ OR KEY_WOW64_64KEY);
  List     := TStringList.Create;
  try
    Registry.RootKey := HKEY_LOCAL_MACHINE;
    if Registry.OpenKeyReadOnly('\SOFTWARE\Microsoft\Windows\CurrentVersion\Run') then
    begin
       Registry.GetValueNames(List);
       Writeln(List.Text);
    end;
    Registry.CloseKey;
  finally
    Registry.Free;
    List.Free;
  end;
end;

begin
  try
   ReadRegistry();
  except
    on E:Exception do
      Writeln(E.Classname, ': ', E.Message);
  end;
  Readln;
end.

If you are targetting the .Net Framework version 4.0 or above then you can do this by passing the RegistryView.Registry32 value when opening the desired registry key.

If you are targetting a previous version of the .Net Framework then you need to use P/Invoke to call RegOpenKeyEx directly yourself allowing you to pass the KEY_WOW64_32KEY flag.

There is a guide here that goes into more detail:

• How to read the 64 bit registry from a 32 bit application or vice versa