These problems are mostly a result of corrupted DLL files in the MTA installation folder (usually "Program Files > MTA San Andreas 1.5 > MTA") or a corrupted MTA launcher executable.Because files like this are MTA data files, they will cause you to be kicked if damaged, as MTA continuously checks their integrity.It was externally modified by something, which is why it's assumed that your PC is infected with a virus, as viruses are often capable of locating and modifying files.Solution is to Run a full antivirus scan, then re-install MTA so that the data file is restored to original, and, if you did, don't again touch or replace DLL files in the MTA installation directory.
Are you using a trainer/cheat program? If so, check if there's any running in the background and close it.
@Music I saw you in-game, is your issue fully resolved?