I was running Prezi 5.0.5 and updated Adobe Acrobat Reader to the latest version, 11.0.06. After the update, Prezi stopped opening. I uninstalled Adobe using the instructions from this page:
http://www.ehow.com/how_6245350_unins...
and installed the previous version. Then, Prezi started working again.
http://www.ehow.com/how_6245350_unins...
and installed the previous version. Then, Prezi started working again.