There was a time when PC games were sold exclusively on floppy disks and CDs. PC games in the early second half of the 90s, sold on CD, had a cunning (but not ideal) system of protection against piracy. If you installed such a game from a disc, then without it in the drive you could not run it.
Nowadays, you can make it much easier by mounting an image of the game, but images of ancient PC games (like nrg, img, cue, etc.) take up at least two / three times more space than the game itself installed from the same image. This is where the NOCD crack comes in handy, allowing you to run the game without having to store and mount a large image. It is unlikely that there is a need for a NOCD crack for GTA1 now, but if you find such a rare version of GTA1 that requires a CD, then you may well use this crack. Move the contents to the directory of the installed game, open the .reg files (if you have London GTA, then open "LONDON.REG"), then open "GTACRACK.EXE". Just drag "GTACRACK.EXE" to the DOSbox icon and the crack will do it all by itself. The crack works absolutely with any CD-version of GTA1! Even with the most ultra-mega-rare, including the London versions.
Warning: We do not support piracy or license circumvention and recommend using licensed products. In this case, GTA1 discs have not been sold for a long time, and the licensed version of this game cannot be purchased anywhere.
Bonus: In the archive with NOCD-crack, as a bonus, there are wallpapers for the desktop in the amount of one image. The image is calculated on monitors with a resolution of 1024x768. Wallpaper from the author of NOCD-crack for GTA1.