dxdiags.exe is a Trojan.Certif-G. dxdiags.exe monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\dxdiags.exe More info: http://www.sophos.com/virusinfo/analyses... Removal: Kill dxdiags.exe process and remove dxdiags.exe from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.