I've just got hold of a used Casio FX-CG20 calculator but I want to change the Owner, Company information BUT it's password protected. I've hunted the Web and can only find answers like Casio or your retailer have to do it, and I also found a solution (which doesn't work) involving holding down 3 keys whilst pressing on the restart button on the back which would need a contortionist to operate it! Is there no hard reset buried somewhere, the reset to Factory Default still leaves the previous owner. Any help would be appreciated.

What operating system vertion do you have?

OS 02.00.0200

I've done it. You switch CG20 off. Then press OPTN+UP+AC. Screen lights up and asks you to press F1 to delete the Owner. After that you can go to setup and find Owner, Company and Password fields blank and you can then press Edit and put your information in.