perfmnt.exe is a Trojan.Agent-EY. perfmnt.exe monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\perfmnt.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill perfmnt.exe process and remove perfmnt.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.