No, you will not lose the game. If you upgrade Amazing Adventures The Lost Tomb, it means that you will install a new version of the game on your computer. The upgrade will not delete or replace the files of the old one. The game versions are: Amazing Adventures: Around the World, Amazing Adventures: The Caribbean Secret, Amazing Adventures: The Forgotten Dynasty, Amazing Adventures: The Lost Tomb and Amazing Adventures: The Riddle Of The Two Knights and you can purchase them from the official web page.