winmssg.exe is a Trojan W32.Rbot-ATW. winmssg.exe opens a back door on IRC channels. winmssg.exe spreads via open network shares. winmssg.exe tries to terminate antiviral programs installed on a user computer. winmssg.exe monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\winmssg.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill winmssg.exe process and remove winmssg.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.