How can I force Captivate 9 to republish a cptx project?

Hello, I am a Newbie to Captivate and am using the latest version of Captivate 9. I  have created a responsive cptx project that incorporates a large video demo and quiz. I wanted to use the action 'Open another project', triggered by the user clicking on a box. I was testing whether the action (open other project) had worked but wasn't having any success. In attempting to understand why 'Open other project' wasn't working, I published the project to my computer. Since then I have given up on 'Open other project' for another time, and I have made extensive changes to the project. I want to publish the project to my computer to generate a SWF file but the option Publish to My Computer is no longer available for some reason that I can't identify. My choices are Publish to devices, Publish device app, Publish to Acrobat.com, and Publish to cloud, or via the File>Publish menu, which allows me to publish an html5. I have checked all the preferences I can find, both global and project. I have opened and closed the software and rebooted my computer (getting desperate!). I have changed slides, added slides, deleted slides, everything I can think off to have the software allow me to publish to my computer. I have cleared the cache and moved the original SWF file out of the Working directory and Project directory. How can I force Captivate 9 to republish this project? How can I publish the project as an MP4? 

Thanks, Amanda