Sfool.exe is a network-aware worm W32.Randex.EUS. Sfool.exe opens a back door through IRC channels. Sfool.exe spreads via open network shares. Sfool.exe tries to terminate antiviral programs installed on a user computer. Related files: %System%\sfool.exe Adds the value: "mssfos" = "sfool.exe" to the Windows startup registry keys. More info: http://securityresponse.symantec.com/avc... Removal: Kill sfool.exe process and remove sfool.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.