antivirus_update.exe is a worm W32.Erkez-G. antivirus_update.exe spreads via e-mail. Related files: %System%\AntiVirus Update.exe %System%\antivirus_update.exe %System%\foto5.jpz More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill antivirus_update.exe process and remove antivirus_update.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.