Regarding the problem of Casio Prizm calculators that hang on the power-off screen and then die when rebooted, I have the feeling that we [the Casio programming enthusiast community] have discussed this subject way more than Casio ever did – in the end, it may be easier and cheaper to fix or replace, say, 1% of the calculators they sell, than to pay lots of working hours to discuss and fix hard-to-reproduce bugs, delaying the production of newer models (in the end, nowadays people buy a calculator because it’s fancy, not because it will survive the apocalypse ).
To all the users with dead calculators… I know your situation is bad (especially if you didn’t have backups of the data in it), but just send the f***ing thing for repairs before the three year warranty expires. Make sure to explain how it broke, maybe they will fix it some day. And when the warranty expires, if you still need a graphic calculator, well, buy a new one (eventually not from Casio?).