How to remove "Your system was infected by dangerous Trojan" message

"Your system was infected by dangerous Trojan" is a fake message generated by fake spyware cleaners (like IEDefender and Files Secure).

System Error!
Your system was infected by dangerous Trojan.
Note: Your critical files can be lost!
Click OK to download antimalware application to clean your system! (Recommended)

This fake warning may slow your computer and cause critical Windows errors. We recomend to remove this popup using automatical removal tool.

Dangerous Trojan Remover for Windows Vista and XP