msn5.exe is a Trojan W32.Agobot-TW. msn5.exe opens a back door. msn5.exe spreads via open network shares. Related files: %System%\msn5.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill msn5.exe process and remove msn5.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.