iSpring Free- not free for school
I am aware some schools use iSpring Free to convert .PPT and .PPTX documents into SWF format "movies" to upload to their VLE. Please be aware that this use is explicitely excluded in the licence agreement which states-
iSpring Solutions grants you a limited, non-exclusive, non-transferable, non-renewable license to install, use, access, display, run, or otherwise interact with ("RUN") the Software Product. The Software Product is provided to you as a freeware for your own personal use only, and it may not be used for any commercial or educational purposes, at educational institutions or non-profit organizations. For commercial or educational use that includes all fields that do not belong to pure private use: e.g. all kinds of use in the range of any profession or for the utilization of additional professional features, you must license the professional versions which are subject to charging.