This program shows you the registry keys accesibility, it checks 3 different permission for the key: READ, READ-WRITE, and ALL-ACCESS (of course you can expand the list with adding new access check in the code).Author just wants to show you that you should not use delphi's registry unit in NT's platform.Author suggests you then to replace any reference to Registry unit with the patched version (RegistrA.pas) which acompanied with this distribution code. Actually, it doesn't do so much, just provides an access option when opening a key, which will inherited in further consecutive operation (read/write-etc).This code also shows you a simple technique to get the system error message.