Expin.dll is a Adware.MediaInject. Expin.dll displays advertisements. Expin.dll monitors user Internet activity. Related files: Micore.exe Runc.exe Expin.dll Wrdget.dll Adds the value: "micore"= "%ProgramFiles%\micore\runc.exe" to the Windows startup registry keys. More info: http://securityresponse.symantec.com/avc... Removal: Remove Expin.dll from Windows startup using antivirus (also check How To Remove section)Startup Optimizer.