SystemDll.exe is a Backdoor W32.Rbot-AJR. SystemDll.exe tries to terminate antiviral programs installed on a user computer. SystemDll.exe monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\SystemDll.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill SystemDll.exe process and remove SystemDll.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.