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