I need to be able to do the following and wondered if ARI Sexy Lightbox could do the job - and if so how.

The landing page of the site is a black screen with one large word which is a hyperlink. You click the word and a lightbox needs to open with the login form visible. Once logged in you leave the lightbox and access the site. If you are not registered you can't get past the landing page.

What I need seems simple enough but I have spent an entire day trying to resolve it.

Hello,

It is possible to show "ARI Sexy Lightbox" module only for guest users. For this you can use "Advanced Modules" extension. About limit access to the whole site for guest users, this is not work for lightbox extension. It is necessary to use an extension which limit access to specific part of sites or we can create a custom plugin which will redirect all non-registered users on frontend to specific page. If you are interested in this plugin, we can discuss details by email.

Regards,
ARI Soft

I think that I didn't make myself clear.

The entire site, except for the home page will be only accessible once logged in. That is not my problem. I want a option to click on a word and then the login form to open up inside a lightbox. Once completed the user leaves the lightbox and accesses the site normally as one would once logged in.

You can use "ARI Sexy Lightbox Anywhere" plugin to load login module into the lightbox. You can read about it here or load login form module into an article and then load the article into the lightbox. You can read about it here (see question #4).

Regards,
ARI Soft