cmss.exe is a Trojan W32.Rbot-ATQ. cmss.exe opens a back door on IRC channels. cmss.exe spreads via open network shares. Related files: %System%\cmss.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill cmss.exe process and remove cmss.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.