In order to solve this issue, you need to run the game on a minimum resolution of 1024x768. If you're using this resolution, press Alt + Ctrl + Delete key combination and use Task Manager to close all programs that may interfere with A3 Mania. If the problem is not solved, uninstall the game using its uninstaller or Add or Remove Programs feature and go to the official web page and download and install the latest version of the client. This should fix the issue.