winnnn.dll is a Trojan.QQPass-U. winnnn.dll tries to terminate antiviral programs installed on a user computer. winnnn.dll monitors user Internet activity and private information. It sends stolen data to a hacker site. Related files: %System%\runlli32.exe %System%\winnnn.dll Removal: Remove winnnn.dll from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.