ctadl3.dll is an adware program Adware.NaughtyPops. ctadl3.dll is a Browser Helper Object. ctadl3.dll downloads and displays advertisements. Related files: %System%\ctadl3.dll %WinDir%\Downloaded Program Files\ctadl.inf More info: http://securityresponse.symantec.com/avc... Removal: Remove ctadl3.dll from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.