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