I'm vision impaired & desperately in need of "Big Button" key board, I downloaded the free version to try & absolutely love it, so I decided to upgrade & buy the full function deluxe version, for the life of me I tried every trick in the book to download it BUT IT KEEPS GIVING ME ERROR 24, I don't want to uninstall the free version for fear I wont be able to reinstall it. any gurus out there that can help?? Thanks!!!