After verification, launch the game. If you get an immediate "failed to start" error, proceed to Method 3.
The error related to Buddha.dll in Call of Duty: Black Ops 2 is almost always caused by (especially the popular "Buddha" mod menu for zombies mode), not by a missing Windows system file. If the game fails to load this DLL, it’s because the mod menu installation is incomplete, blocked, or incompatible. How To Fix Buddha.dll In Black Ops 2
DLL errors are frequently linked to outdated or corrupted system components. After verification, launch the game
Newer versions of Windows (10 and 11) may require specific settings to run older game files properly: How To Fix Buddha.dll In Black Ops 2
If the file exists but Windows cannot see it, manually register it using the command line.