Okay, an update. I did figure out what you meant: deactivated the subscribe2 plugin, went to my phpmyadmin page on my webhost control panel, dropped the subscribe2 tables, reactivated the plugin.
Still the same situation.
I also tried deactivating Theme My Login plugin. The page kept the theme with [theme-my-login-page] at the top of the page. When I reactivated it, both logins returned.