Could publish and can't now - how to isolate desk change

For years and until recently, I have been successfully publishing presenter courses that include Captivate swf files embedded in Engage files. 

Something on my desktop has changed and the Captivate-produced-Engage media no longer publishes correctly in Articulate (although it does publish correctly as an Engage file). I know this is the problem because

- all my (captivate SWF-Engage-Articulate) PowerPoint files no longer publish correctly on my computer

- one "problem" (captivate SWF-Engage-Articulate) file publishes correctly when I port it to an old computer and republish.

My goal is to change/fix my desktop so I can continue to create/publish files like these now and in the future.  What am I looking for?  Is it the  virus-checker?  Is it another plug-in to MS Powerpoint?  Was there an automatic patch that updated articulate and created this issue? 

Thanks for whatever help you might provide.