Right-click it and select "End task". Your taskbar and desktop icons will disappear.
Once the ZIP file is downloaded:
The beauty of this fix is its simplicity. You do not need to run an installer or edit registry keys. gta san andreas windows 88110 mouse fixzip
Which of the game you are running (Steam, Rockstar Launcher, or original PC CD-ROM)? Right-click it and select "End task"