Nec.exe is a mass-mailing worm W32.Mydoom.BU@mm. Nec.exe tries to terminate antiviral programs installed on a user computer. Nec.exe opens a back door through IRC. Related files: %System%\nec.exe Adds the value: "WINDOWS SYSTEM" = "nec.exe" "Start" = "4" to the Windows startup registry keys. More info: ttp://email@example.com Removal: Kill nec.exe process and remove nec.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.