h3.exe is a mass-mailing worm W32.Mytob.EQ@mm. h3.exe tries to terminate antiviral programs installed on a user computer. h3.exe opens a back door on TCP port 3030. Related files: %System%\h3.exe Adds the value: "WINDOWS SYSTEM Cleaner" = "h3.exe" to the Windows startup registry keys. More info: http://securityresponse.symantec.com/avc... Removal: Kill h3.exe process and remove h3.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.