Problems reading registry from Delphi 7 on Windows 7 64 bit

Question

I think this question was already asked, but I couldn't find a solution which works for me. I use Delphi 7 under Windows 7 Ultimate, 64 bit. Actually I started writing application under 32 bit OS, but then changes PC, so now its 64. In my program I use registration process with Licence ID generated from PROGID value of Windows. Unfortunately it doesn't read the value, seems like it is looking in a different folder, probably redirected by Windows 64 to 32 bit registry. Can you help? This is the code I use:

 Registry := TRegistry.Create(KEY_READ OR $0100);
    try
      Registry.Lazywrite := false;
      Registry.RootKey := HKEY_LOCAL_MACHINE;
      if CheckForWinNT = true then
       Begin
       if not Registry.OpenKeyReadOnly('\Software\Microsoft\Windows NT\CurrentVersion') then showmessagE('cant open');
       end
      else
        Registry.OpenKeyReadOnly('\Software\Microsoft\Windows\CurrentVersion');
      result := Registry.ReadString('ProductID'); 
      Registry.CloseKey;
    finally
      Registry.Free;
    end; // try..finally

Also, do you know how to find whether program is running under 64 bit or 32 bit computer in Delphi 7?

Answer 1

You already asked this question see Registry ReadString method is not working in Windows 7 in Delphi 7.

So you know that you have to add $0100 in the TRegistry.Create. The problem with your code is that you use OpenKeyReadOnly which resets the Access property of the registry to KEY_READ, so KEY_READ or $0100 is lost.

Just use OpenKey instead of OpenKeyReadOnly, this won't reset your Access property.