How to uninstall complete SClogin because conflict with thirtypart?

You should uninstall it using the Joomla Extension Manager. It should uninstall just like any other extension. When done, clear your Joomla and browser caches in case any assets have been cached.

If you're still having problems, please let me know specifically what is going wrong and a page where we can see the issue. We'll gladly take a look.

Thanks,
Alex