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