I currently use the SClogin module for user’s accounts But I have other applications that if the user is not log in refers them to the Joomla Standard login form (which is disabled as is the community builders)
How do I replace the standard Joomla login screen with the SClogin?
Unfortunately, you can't. The SCLogin module is just that.. a module. When an extension tries to redirect a user, it goes to the Joomla User Component's login page. The only thing you could do is:
* Setup a redirect from the standard Joomla login page to a custom article or other page
* On that custom page, set the SCLogin module to display
That could work, but it wouldn't force the SCLogin module to popup on whichever page requested the login view, as I think is what you're looking for.
I hope that helps explain,