[Plugin: UnderConstruction] Will not deactivate!

I’ve used this plugin many times – mostly to redirect visitors to the old HTML version of a site while WordPress is under construction, and I really like the plugin – have had no problems with it until now.

Now it is showing only the default UnderConstruction “http://libertyequestrian.com is coming soon” page, even with the plugin entirely deleted.

It’s possible this is a caching issue… however… I’m using Safari with Web Developer tools enabled and caches disabled. I’m also testing on Firefox with Firebug installed and caches disabled. Have also been using shift-command-R on Firefox repeatedly to force a clean reload, and am not getting any results. Currently the UnderConstruction plugin is deleted from my WordPress install and I’m still seeing the default UC “coming soon” page for this site.

I can see the WordPress site when I’m logged in, and have not had problems logging in so far.

WP Super Cache was installed by my web host, but deactivating it during development was one of the first things I did. I also briefly removed the WP Super Cache code from my .htaccess file but there was no change in the UC plugin behavior.

This is not a networked WordPress install. Single site only.

Website is http://libertyequestrian.com/ – any advice much appreciated. I can supply copy of any code as needed. Thanks!