To unlock all 771 cards in the Yu-Gi-Oh! Power of Chaos trilogy (Yugi the Destiny, Kaiba the Revenge, and Joey the Passion), you need to manage a shared file called system.dat located in the game's "Common" directory.  The Legend of the "Common" Folder 

Administrator Mode: Always run the game as an administrator on Windows 10/11; otherwise, the game may fail to save your progress or recognize the unlocked cards.

Using an automated installer is the fastest and most reliable method for modern systems like Windows 10 and 11.

2. "I unlocked God Cards, but I can't summon them!"

Locate the Common Folder: This is typically found in the installation directory of the last game you installed (usually Joey the Passion).