Problem editing text converted to mesh I have a problem with my text.

When I press the TAB key I can not change the text from "CINEBRICK STUDIOS" to "******* STUDIOS". It just shows like a wireframe. The text was previously converted to a mesh.

I watched the video and imitated everything perfectly. At first everything went well. I could change the text with the TAB key. However I want to change it again, which does not work. It was a long time ago when I imitated this video. Original video link (YouTube): https://www.youtube.com/watch?v=do0jF3zb5_U

Here are a few pictures of the current situation.
What you're seeing is the wireframe of the mesh when you're switching to edit mode by pressing the Tab key. 

Once you've converted your text object into a mesh you can't edit the text anymore. Since the conversion is not reversible you will have to create a new text object perform the desired changes to the text and then convert it into a mesh.