Trojan:A trojan (or Trojan horse) is a small malicious program that pretends to have a particular function, but that only shows its real purpose after execution and that purpose is often destructive. Trojans cannot multiply themselves, which differentiates them from viruses and worms.
Trojan.FakeSecSen is a Trojan horse capable of being installed onto your computer system without your knowledge or approval, and going undetected by most anti-spyware applications. Once active, Trojan.FakeSecSen may begin downloading additional malware onto your PC, and allow remote hackers to gain access to your personal and financial information.
Technical details (How to remove Trojan.FakeSecSen(pop up))