For Project IGI: I'm Going In , a "No-CD" crack or patched executable is primarily used by owners of the original 2000 release to run the game on modern Windows systems (10/11) without the physical disc, which often fails to authenticate due to outdated DRM.  Modern Compatibility & Patches 

• Forces correct rendering (disable DirectDraw emulation issues).
• Sets CPU affinity to avoid crashes on multi-core systems.
• Adds a borderless window option and resolution scaling fix.

• Engaging stealth gameplay
• Intelligent AI
• Immersive sound design
• Decent graphics for its time

• One-time check to ensure user owns a legitimate copy before applying patch.

(as a backup) and paste the patched version into the same folder. Better Alternatives for Modern PCs