When Flip is introduced through an infected file, the virus checks if there is already a copy of itself in memory and that the memory is not full. If it is, the virus quits running, Wikia says. If not, it becomes memory resident. The virus then checks if the master boot record has been infected, and if it is not, infects it. The virus appends its code to any .com or .exe files that are executed. Files with an .ovl extension will also be infected if used by a file that becomes infected.