Are you typing on a layer that's above the layer that's showing? Is the Opacity and Fill 100%?
If not that, you may have something set in the Character panel that's making it behave differently than you expect. My first advice would be to Reset the Type tool and try again. You'll have to set the font and size, etc., again, but after that you should be able to lay down some text.
I have tried everything. Nothing is working. When I make a change, I get the message "rendering type". Doesn't matter what I try and change and this comes up.
Getting very frustrated.
there are these digimarks, do you know them? Please have a look there: Digimarc (DMRC) - Enable Media the Digimarc Way.
A problem could be "Digimarc plug-ins require a 32-bit operating system. They are unsupported in 64-bit versions of Windows and Mac OS."
In any case here's a link to an Adobe website helpx.adobe.com/photoshop/using/digimarc-copyright-protection.html.
On the other hand here's a video about crating watermarks: http://www.youtube.com/watch?v=4eoWzMMVtMs