Hello to everyone, mortal thank you very much. IT WORKS. I can't believe it. To everyone who has the same or similar problem: Do it like mortal said: GP4 out of the box official patch decrypted exe gpx_patch and then csm Test it after each step so that you can say when there is problem. The most important point is: run the executable in Win98 compatibility mode! In the end I cby curbsdriver - Grand Prix 4