If the official patch does not work for your specific version, or if you prefer to keep an exact digital copy of your original disc, you can use "Mounting." This tricks your computer into thinking a file on your hard drive is a real physical CD.
In the late 1990s and early 2000s, Project I.G.I.: I'm Going In
If you were a PC gamer in the early 2000s, your hard drive likely contained two things: a heavily fragmented Windows 98 or XP installation, and a copy of Project I.G.I.: I’m Going In . Released in December 2000 by Innerloop Studios and published by Eidos Interactive, this tactical first-person shooter was a revelation. It offered massive, open-ended outdoor levels, a realistic damage model, and a complete lack of a health bar—one shot to the head, and you were done.
However, a significant subset of users were "preservationists" or "convenience gamers." These were individuals who owned the legitimate box copy but found the DRM (Digital Rights Management) intrusive.
: Physical CDs degrade over time ("disc rot"), making digital-only or "No CD" versions essential for preserving the game for future play. How to Play Without a CD Legally
