Thank you for your response to my previous attempt to solve my problem. You referred me to a pinned post that I had already read before posting and which which was not, as far as I can tell, relevant. The problem is that I cannot get to the admin login page at all now using the same URL ( mydomain/cart/index.php?rt=index/login|s=your_admin) that worked perfectly well after installation.
Instead of the login page for admin, I get an error "The page you requested cannot be found!" from within a store page. My question is; is the URL I quote above correct or have I made a mistake in using it? If it is correct, some help in resolving the problem of accessing admin would be much appreciated.
Thank you.
PS Having read another post on this subject, the content of config.php is: define('ADMIN_PATH', 'your_admin');
