The original game relies on a file called MCM2.ICD and the main executable to verify you have the CD in the drive. Since Windows 10/11 won't even load the drivers needed for that verification, the game simply won't launch. A No-CD patch replaces the original MCM2.EXE with a modified version that skips this check, allowing the game to boot directly from your hard drive. How to Get MCM2 Running on Modern Windows
If the game launches but fails to detect your graphics card, you may need to edit the registry:
The no CD patch, a modification to the game's code, was developed to bypass the CD-ROM authentication checks. This patch allowed players to run the game without inserting the CD, resolving the inconvenience and potential data loss associated with the original copy protection mechanism. The patch worked by emulating the expected CD data, effectively tricking the game into thinking the CD was present.